The optimized molecular structures and vibrational frequencies of 4-mercaptopyridine(4MPY) monomer and its dihydrate were studied by means of the density functional theory( DFT), viz. B3LYP method with the 6-311 ...The optimized molecular structures and vibrational frequencies of 4-mercaptopyridine(4MPY) monomer and its dihydrate were studied by means of the density functional theory( DFT), viz. B3LYP method with the 6-311 + + G (d,p) basis set. On the basis of the calculations, the assignments of the vibrational spectra of the monomer and the dihydrate were performed, and so were investigated the changes in the structure and the vibrational spectrum of the di- hydrate as well as the intermolecular force resulting in the formation of the dihydrate. The calculated results show that each of the water molecule planes is vertical to the pyridine ring plane in the dihydrate that is formed via the H-bonds between 4MPY and water molecules. Furthermore, the structure and the vibrational spectrum of 4MPY can be considerably affected by the water molecules.展开更多
In this paper, we have applied the Lie algebraic model to nano-bio molecules to determine the vibrational spectra of different stretching and bending vibrational modes. The determined vibrational energy levels by the ...In this paper, we have applied the Lie algebraic model to nano-bio molecules to determine the vibrational spectra of different stretching and bending vibrational modes. The determined vibrational energy levels by the Lie algebraic model are compared with the experimental data. The results from the theoretical mode[ are consistent with the experimental data. The vibrational energy levels are clustering in the excited states.展开更多
Criegee intermediates are of signi cance in the atmospheric chemistry.In this work,the rovibrational spectra of the simplest deuterated Criegee intermediate,CD2OO,were studied by a vibrational self-consistent eld/virt...Criegee intermediates are of signi cance in the atmospheric chemistry.In this work,the rovibrational spectra of the simplest deuterated Criegee intermediate,CD2OO,were studied by a vibrational self-consistent eld/virtual con guration interaction(VSCF/VCI)method based on a nine-dimensional accurate potential energy surface and dipole surface for its ground electronic state.The calculated fundamental vibrational frequencies and rotational constants are in excellent agreement with the available experimental results.These data are useful for further spectroscopic studies of CD2OO.Especially,the rotational constants for excited vibrational levels are essential for experimental spectral assignments.However,the infrared intensities from di erent resources,including the current computation,the experiment,and previous calculations at the NEVPT2 and B3LYP levels,deviate signi cantly.展开更多
An improved U(2) algebraic model is introduced to study the stretching and bending vibrational spectra of methane and its isotopomers.The algebraic model with fewer parameters reproduces the experimental spectra wit...An improved U(2) algebraic model is introduced to study the stretching and bending vibrational spectra of methane and its isotopomers.The algebraic model with fewer parameters reproduces the experimental spectra with good precision.Moreover,the obtained parameters describe well the correct behavior of isotopic substitution.It is shown that the Fermi resonance leads to a very fast intramolecular vibrational redistribution among stretches and bends.展开更多
Semi-empirical method PM3 was used to study the geometry and vibrational spectrum of N-(2-hydroxy-l-naphthyl-methylene)-l-pyrenamine (NPY) with the intermediate hydrogen bond. Results are comparable to experimentation...Semi-empirical method PM3 was used to study the geometry and vibrational spectrum of N-(2-hydroxy-l-naphthyl-methylene)-l-pyrenamine (NPY) with the intermediate hydrogen bond. Results are comparable to experimentations. Based on results of both NPY and its model, N-(2-hydroxy-l-naphthyl-methylene)aniline, it was found that the N-(2-hydroxy-l-naphthyl-methylene) group is principally responsible for the special hydrogen bonding through conjugation effect.展开更多
Vibrational transition spectra of H2+ in an ultra-strong magnetic field are determined. The validity of Born- Oppenheimer approximation is analyzed based on one-center method and B-spline basis sets. It is shown that...Vibrational transition spectra of H2+ in an ultra-strong magnetic field are determined. The validity of Born- Oppenheimer approximation is analyzed based on one-center method and B-spline basis sets. It is shown that Born- Oppenheimer approximation is reliable for the investigation on the ground state and low excited states of H2+ subjected to the strong magnetic field. Furthermore, it is found that the vibrational transition spectra from lσg, lπu, and 1δg states lie in infrared, visible, and ultraviolet ranges with increasing magnetic field strength.展开更多
Density functional theory BLYP (using Becke's and Lee-Yang-Parr's correlation functionals), nb initio Hartree-Fock (HF) and hybrid DFT/HF B3LYP calculations were carried out to study the structure and vibratio...Density functional theory BLYP (using Becke's and Lee-Yang-Parr's correlation functionals), nb initio Hartree-Fock (HF) and hybrid DFT/HF B3LYP calculations were carried out to study the structure and vibrational spectra of 4-methyl-3-penten-2-one. The BLYP/6-31G* and scaled HF/6-31G* frequencies correspond well with each other and with available experimental assignment of the functional vibrational modes.展开更多
Optimized geometry and harmonic vibrational frequency of 2-dicyanovinyl-5-(4- ethoxyphenyl)thiophene (C16Hj2N2OS) are calculated at the HF/6-31++G(d,p) and B3LYP/6- 311 ++G(d,p) levels. Mulliken charges in...Optimized geometry and harmonic vibrational frequency of 2-dicyanovinyl-5-(4- ethoxyphenyl)thiophene (C16Hj2N2OS) are calculated at the HF/6-31++G(d,p) and B3LYP/6- 311 ++G(d,p) levels. Mulliken charges in the ground state are also calculated. The research shows the presence of intermolecular interaction in the title compound. The scaled harmonic vibrational frequencies have been compared with experimental FT-IR spectra. A detailed interpretation of the infrared spectra of the title compound is reported. The theoretical spectrograms for IR spectra of the title compound have been constructed, The isotropic chemical shift computed by 13C and 1H NMR analyses also shows good agreement with the experimental observations.展开更多
Harmonic vibrational frequencies of hydrazoic acid and methyl azide are calculated using HF. MP2 methods and five popular density functional (DFT) methods and compared with experimental results. Of these seven methods...Harmonic vibrational frequencies of hydrazoic acid and methyl azide are calculated using HF. MP2 methods and five popular density functional (DFT) methods and compared with experimental results. Of these seven methods, BLYP reproduces the observed frequencies most satisfactorily, while the results in HF and MP2 are worse. These indicate the BLYP calculation is a very promising approach for understanding the observed spectral features.展开更多
Density functional theory BLYP (using Becke's and Lee-Yang-Pars's correlation functionals), ab initio Hartree-Fock (HF) and hybrid DFT/HF B3LYP calculations were carried out to study the structure and vibratio...Density functional theory BLYP (using Becke's and Lee-Yang-Pars's correlation functionals), ab initio Hartree-Fock (HF) and hybrid DFT/HF B3LYP calculations were carried out to study the structure and vibrational spectra of pyruvic acid. The scaled B3LYP/6-31G* frequencies correspond well with available experimental assignment of the functional vibrational modes and the mean absolut devation is only 12.3cm^(-1).展开更多
Raman spectra of amorphous carbon nitride films (a-C:N) resemble those of typical amorphous carbon (a-C), and no specific features in the spectra are shown due to N doping. The present work provides a correlation...Raman spectra of amorphous carbon nitride films (a-C:N) resemble those of typical amorphous carbon (a-C), and no specific features in the spectra are shown due to N doping. The present work provides a correlation between the microstructure and vibrational properties of a-C:N films from first principles. The six periodic model structures of 64 atoms with various mass densities and nitrogen contents are generated by the liquid-quench method using Car-Parinello molecular dynamics. By using Raman coupling tensors calculated with the finite electric field method, Raman spectra are obtained. The calculated results show that the vibrations of C=N could directly contribute to the Raman spectrum. The similarity of the Raman line shapes of N-doped and N-free amorphous carbons is due to the overlapping of C=N and C=C vibration bands. In addition, the origin of characteristic Raman peaks is also given.展开更多
Methods of optical spectroscopy and X-ray crystallography data were used to examine the effect of architecture of carboxylate anions on structure of the Eu3+ coordination centre in europium earboxylates with 1,10-phe...Methods of optical spectroscopy and X-ray crystallography data were used to examine the effect of architecture of carboxylate anions on structure of the Eu3+ coordination centre in europium earboxylates with 1,10-phenanthroline Eu(RCOO)3·Phen. Luminescence spectra of europium acetate, nitropropionate, benzoate, naphthylcarboxylates, phenylacetates, phenoxyacetate, triphenylpropionate were investigated. A few of europium carboxylates with 2,2'-bipyridine Eu(RCOO)3·Bpy and europium salts Eu(RCOO)3·nH2O were also studied. Vibrational IR and Raman spectra of phenylacetate family were analyzed. The crystal structure of nitropropionate Eu(NO2C2H4COO)3·Phen was solved by X-my diffraction method. The predominant influence of steric hindrances on Eu^3+ coordination centre was observed at increase of the size of aromatic flagment of carboxylate anions. It was demonstrated, that introduction of the methylene bridges between the carboxylic group and aromatic rings of ligand weakens the effect of steric factor.展开更多
The complete experimental IR spectra and vibrational analysis of the title complex Co(mnt)(dmbpy) were reported in this paper. The results show that the complex molecule has a planar geometry belonging to point group ...The complete experimental IR spectra and vibrational analysis of the title complex Co(mnt)(dmbpy) were reported in this paper. The results show that the complex molecule has a planar geometry belonging to point group C 2v and ground electronic state with spin quartet. A new method for analyzing vibrational spectra of complicated molecule is established. The essential of this method is to point out main fixed points and pivotal vibrational units in assignment for each fundamental band. Two new symbols η (heaving along the specified direction) and M (midpoint of a bond or unit) were defined for describing the vibrational modes accurately.展开更多
The spin crossover(SCO) compound [Fe(bapbpy)(NCS)2],where bapbpy contains two fused N,N-bis(2-pyridyl)amines,has been studied by DFT/TD-DFT/BS-DFT methods.Several density functionals and basis sets were used i...The spin crossover(SCO) compound [Fe(bapbpy)(NCS)2],where bapbpy contains two fused N,N-bis(2-pyridyl)amines,has been studied by DFT/TD-DFT/BS-DFT methods.Several density functionals and basis sets were used in the calculation to obtain optimized geometries of the compound in the low-(LS) and high-spin(HS) states.The vibrational modes and IR spectra,spin splitting energies,excited states and UV/Vis absorption spectra were obtained.The structural parameters of the calculated isolated complex are in good agreement with the X-ray data.We investigate three dimers of [Fe(bapbpy)(NCS)2] complex for their magnetic properties.It has been found that the complex(1,3) has ferromagnetic character while the others are antiferromagnetic in nature by using a broken symmetry approach in the DFT framework(BS-DFT) with support from the coupling constant values(J) and spin density plots.展开更多
The interaction of trivalent lanthanide ions and divalent calcium ions with sph-'ngomyelm bilayer has been studied by FT-Raman spectroscopy.The results showed that the bonding of metal ions to the phosphate group ...The interaction of trivalent lanthanide ions and divalent calcium ions with sph-'ngomyelm bilayer has been studied by FT-Raman spectroscopy.The results showed that the bonding of metal ions to the phosphate group of sphingomyelin bi-iayer,either La3+or Ca2+did not change the conformation of the choline group,that is,O-C-C-N+is still in its gauche conformation.The presence of metal ions changed the states of the interfacial region from liquid-like to amorphous state and even to crystalline.They increased the fluidity of acyl chains of sphingomyelin bilaver and made them packed disorderly.展开更多
We execute the density functional theory(DFT) and time-dependent density functional theory(TDDFT) approaches to make a detailed exploration about excited state luminescent properties as well as excited state intramole...We execute the density functional theory(DFT) and time-dependent density functional theory(TDDFT) approaches to make a detailed exploration about excited state luminescent properties as well as excited state intramolecular proton transfer(ESIPT) mechanism for the novel 2,6-dimethyl phenyl(DMP-HBT-py) system. Firstly, we check and confirm the formation and stabilization of hydrogen bonding interaction for DMP-HBT-py. Via optimized geometrical parameters of primary chemical bond and infrared(IR) spectra, we find O–H··· N hydrogen bond of DMP-HBT-py should be strengthened in S1 state. Insights into frontier molecular orbitals(MOs) analyses, we infer charge redistribution and charge transfer(ICT)phenomena motivate ESIPT trend. Via probing into potential energy curves(PECs) in related electronic states, we come up with the ultrafast ESIPT behavior due to low potential barrier. Furthermore, we search the reaction transition state(TS)structure, the ultrafast ESIPT behavior and mechanism of DMP-HBT-py compound can be re-confirmed. We sincerely wish this work could play roles in further developing novel applications based on DMP-HBT-py compound and in promoting efficient solid emitters in OLEDs in future.展开更多
The kinetic study of in-situ eopolymerization of aniline with o- and p-methylaniline by ammonium persulfate (APS) has been carried out. UV-vis spectroscopic method was used to investigate the course of copolymerizat...The kinetic study of in-situ eopolymerization of aniline with o- and p-methylaniline by ammonium persulfate (APS) has been carried out. UV-vis spectroscopic method was used to investigate the course of copolymerization. Structural characterization was studied by PT-IR spectral analysis. The electronic spectra of the copolymers poly(aniline-co-p-toluidine) and poly(aniline-co-o- toluidine) show blue shift. The shift has been observed in the bands corresponding to π→π^* transition as well as in the exciton transition. The increase in absorbance recorded during the reaction for different concentration of aniline, o- and p-toluidine at various intervals of time of polymerization reaction indicates a growth in the polymer formation. The resulting first-order rate constant was used to calculate the rate of copolymer formation using the rate equation -d[A]/dt = kc^n.展开更多
The stable acetone molecule clusters have been studied by using Becke's threeparameter (B3LYP) density functional theory (DFT) with standard 6-31G(d) basis set. The calculated results show that the optimal stru...The stable acetone molecule clusters have been studied by using Becke's threeparameter (B3LYP) density functional theory (DFT) with standard 6-31G(d) basis set. The calculated results show that the optimal structures of acetone clusters are cyclic and the cycles become larger and larger with the increase of cluster size. The strongest vibration peaks for neutral clusters are C=O stretching vibration. The C=O stretching peaks of cyclic acetone clusters split into double ones when n≥3, the frequencies are red-shifted and corresponding intensifies increase with the increase of cluster Size.展开更多
Quantum chemistry calculations have been performed using Gaussian03 program to compute optimized geometry,harmonic vibrational frequency along with intensities in IR and Raman spectra at RHF/6-31++G^(**)and B3LYP/6-31...Quantum chemistry calculations have been performed using Gaussian03 program to compute optimized geometry,harmonic vibrational frequency along with intensities in IR and Raman spectra at RHF/6-31++G^(**)and B3LYP/6-31++G^(**)levels for phenobarbitone(C12H12N2O3)in the ground state.The scaled harmonic vibrational frequencies have been compared with experimental FT-IR and FT-Raman spectra.Theoretical vibrational spectra of the title compound were interpreted by means of potential energy distributions(PEDs)using MOLVIB program.A detailed interpretation of the infrared spectra of the title compound is reported.On the basis of the agreement between the calculated and observed results,the assignments of fundamental vibrational modes of phenobarbitone were examined and some assignments were proposed.The theoretical spectrograms for FT-IR and FT-Raman spectra of the title compound have been constructed.展开更多
The title molecule, 3-(4-(dimethylamino)benzylidene)-l,5-dioxaspiro[5.5] unde- cane-2,4-dione (I), was synthesized and characterized by elemental analysis, IR, UV-vis spectra and X-ray diffraction analysis. The ...The title molecule, 3-(4-(dimethylamino)benzylidene)-l,5-dioxaspiro[5.5] unde- cane-2,4-dione (I), was synthesized and characterized by elemental analysis, IR, UV-vis spectra and X-ray diffraction analysis. The compound belongs to the triclinic system, space group Pi with a = 6.3640(6), b = 7.7404(8), c = 16.2890(18) A, α = 86.860(2), β = 85.837(2), γ = 79.6720(10)°, V = 786.60(14) A3, D, = 1.331 g/cm3, and F(000) = 336. Geometrical structure of the title compound was optimized by density functional theory (DFT) using B3LYP method with 6-31G** as the basis set. The vibrational frequencies were calculated by the DFT method and the results are consistent with the observed frequencies. The electronic absorption spectra were studied with the time- dependent density functional theory (TD-DFT), showing the calculation results in good agreement with the corresponding experimental data.展开更多
文摘The optimized molecular structures and vibrational frequencies of 4-mercaptopyridine(4MPY) monomer and its dihydrate were studied by means of the density functional theory( DFT), viz. B3LYP method with the 6-311 + + G (d,p) basis set. On the basis of the calculations, the assignments of the vibrational spectra of the monomer and the dihydrate were performed, and so were investigated the changes in the structure and the vibrational spectrum of the di- hydrate as well as the intermolecular force resulting in the formation of the dihydrate. The calculated results show that each of the water molecule planes is vertical to the pyridine ring plane in the dihydrate that is formed via the H-bonds between 4MPY and water molecules. Furthermore, the structure and the vibrational spectrum of 4MPY can be considerably affected by the water molecules.
文摘In this paper, we have applied the Lie algebraic model to nano-bio molecules to determine the vibrational spectra of different stretching and bending vibrational modes. The determined vibrational energy levels by the Lie algebraic model are compared with the experimental data. The results from the theoretical mode[ are consistent with the experimental data. The vibrational energy levels are clustering in the excited states.
基金the Chongqing Municipal Natural Science Foundation(No.cstc2019jcyjmsxmX0087)the National Natural Science Foundation of China(No.21573027 and No.21973009).
文摘Criegee intermediates are of signi cance in the atmospheric chemistry.In this work,the rovibrational spectra of the simplest deuterated Criegee intermediate,CD2OO,were studied by a vibrational self-consistent eld/virtual con guration interaction(VSCF/VCI)method based on a nine-dimensional accurate potential energy surface and dipole surface for its ground electronic state.The calculated fundamental vibrational frequencies and rotational constants are in excellent agreement with the available experimental results.These data are useful for further spectroscopic studies of CD2OO.Especially,the rotational constants for excited vibrational levels are essential for experimental spectral assignments.However,the infrared intensities from di erent resources,including the current computation,the experiment,and previous calculations at the NEVPT2 and B3LYP levels,deviate signi cantly.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11174099)
文摘An improved U(2) algebraic model is introduced to study the stretching and bending vibrational spectra of methane and its isotopomers.The algebraic model with fewer parameters reproduces the experimental spectra with good precision.Moreover,the obtained parameters describe well the correct behavior of isotopic substitution.It is shown that the Fermi resonance leads to a very fast intramolecular vibrational redistribution among stretches and bends.
文摘Semi-empirical method PM3 was used to study the geometry and vibrational spectrum of N-(2-hydroxy-l-naphthyl-methylene)-l-pyrenamine (NPY) with the intermediate hydrogen bond. Results are comparable to experimentations. Based on results of both NPY and its model, N-(2-hydroxy-l-naphthyl-methylene)aniline, it was found that the N-(2-hydroxy-l-naphthyl-methylene) group is principally responsible for the special hydrogen bonding through conjugation effect.
基金Supported by the National Basic Research Program of China (Grant No. 2010CB832803)
文摘Vibrational transition spectra of H2+ in an ultra-strong magnetic field are determined. The validity of Born- Oppenheimer approximation is analyzed based on one-center method and B-spline basis sets. It is shown that Born- Oppenheimer approximation is reliable for the investigation on the ground state and low excited states of H2+ subjected to the strong magnetic field. Furthermore, it is found that the vibrational transition spectra from lσg, lπu, and 1δg states lie in infrared, visible, and ultraviolet ranges with increasing magnetic field strength.
文摘Density functional theory BLYP (using Becke's and Lee-Yang-Parr's correlation functionals), nb initio Hartree-Fock (HF) and hybrid DFT/HF B3LYP calculations were carried out to study the structure and vibrational spectra of 4-methyl-3-penten-2-one. The BLYP/6-31G* and scaled HF/6-31G* frequencies correspond well with each other and with available experimental assignment of the functional vibrational modes.
基金Supported by the National Natural Science Foundation of China (No. 10774039)the key project of Henan Educational Committee (No. 12A140004)Henan University of Science and Technology for Young Scholars (No. 2009QN0032)
文摘Optimized geometry and harmonic vibrational frequency of 2-dicyanovinyl-5-(4- ethoxyphenyl)thiophene (C16Hj2N2OS) are calculated at the HF/6-31++G(d,p) and B3LYP/6- 311 ++G(d,p) levels. Mulliken charges in the ground state are also calculated. The research shows the presence of intermolecular interaction in the title compound. The scaled harmonic vibrational frequencies have been compared with experimental FT-IR spectra. A detailed interpretation of the infrared spectra of the title compound is reported. The theoretical spectrograms for IR spectra of the title compound have been constructed, The isotropic chemical shift computed by 13C and 1H NMR analyses also shows good agreement with the experimental observations.
文摘Harmonic vibrational frequencies of hydrazoic acid and methyl azide are calculated using HF. MP2 methods and five popular density functional (DFT) methods and compared with experimental results. Of these seven methods, BLYP reproduces the observed frequencies most satisfactorily, while the results in HF and MP2 are worse. These indicate the BLYP calculation is a very promising approach for understanding the observed spectral features.
基金This work was supported by the Natural Science Foundation of Shandong Province. the National Key Laboratory Foundation of Cry
文摘Density functional theory BLYP (using Becke's and Lee-Yang-Pars's correlation functionals), ab initio Hartree-Fock (HF) and hybrid DFT/HF B3LYP calculations were carried out to study the structure and vibrational spectra of pyruvic acid. The scaled B3LYP/6-31G* frequencies correspond well with available experimental assignment of the functional vibrational modes and the mean absolut devation is only 12.3cm^(-1).
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11074061 and 50972031)the Natural Science Foundation for Youth of Heilongjiang Province of China (Grant No. QC2010006)+1 种基金the Science and Technology Plan of Heilongjiang Provincial Education Department, China (Grant No. 12511163)the Foundation for Young Key Scholars of Harbin Normal University, China (Grant No. 11KXQ-08)
文摘Raman spectra of amorphous carbon nitride films (a-C:N) resemble those of typical amorphous carbon (a-C), and no specific features in the spectra are shown due to N doping. The present work provides a correlation between the microstructure and vibrational properties of a-C:N films from first principles. The six periodic model structures of 64 atoms with various mass densities and nitrogen contents are generated by the liquid-quench method using Car-Parinello molecular dynamics. By using Raman coupling tensors calculated with the finite electric field method, Raman spectra are obtained. The calculated results show that the vibrations of C=N could directly contribute to the Raman spectrum. The similarity of the Raman line shapes of N-doped and N-free amorphous carbons is due to the overlapping of C=N and C=C vibration bands. In addition, the origin of characteristic Raman peaks is also given.
基金supported by the Russian Foundation for Basic Research (N 08-02-00424-a, N 06-03-32557-a)
文摘Methods of optical spectroscopy and X-ray crystallography data were used to examine the effect of architecture of carboxylate anions on structure of the Eu3+ coordination centre in europium earboxylates with 1,10-phenanthroline Eu(RCOO)3·Phen. Luminescence spectra of europium acetate, nitropropionate, benzoate, naphthylcarboxylates, phenylacetates, phenoxyacetate, triphenylpropionate were investigated. A few of europium carboxylates with 2,2'-bipyridine Eu(RCOO)3·Bpy and europium salts Eu(RCOO)3·nH2O were also studied. Vibrational IR and Raman spectra of phenylacetate family were analyzed. The crystal structure of nitropropionate Eu(NO2C2H4COO)3·Phen was solved by X-my diffraction method. The predominant influence of steric hindrances on Eu^3+ coordination centre was observed at increase of the size of aromatic flagment of carboxylate anions. It was demonstrated, that introduction of the methylene bridges between the carboxylic group and aromatic rings of ligand weakens the effect of steric factor.
基金Supported by the National Natural Science F oundation of China( No. 2 97710 2 5 )
文摘The complete experimental IR spectra and vibrational analysis of the title complex Co(mnt)(dmbpy) were reported in this paper. The results show that the complex molecule has a planar geometry belonging to point group C 2v and ground electronic state with spin quartet. A new method for analyzing vibrational spectra of complicated molecule is established. The essential of this method is to point out main fixed points and pivotal vibrational units in assignment for each fundamental band. Two new symbols η (heaving along the specified direction) and M (midpoint of a bond or unit) were defined for describing the vibrational modes accurately.
基金Supported by the Natural Science Foundation of Shandong Province(No.Y2006B43)
文摘The spin crossover(SCO) compound [Fe(bapbpy)(NCS)2],where bapbpy contains two fused N,N-bis(2-pyridyl)amines,has been studied by DFT/TD-DFT/BS-DFT methods.Several density functionals and basis sets were used in the calculation to obtain optimized geometries of the compound in the low-(LS) and high-spin(HS) states.The vibrational modes and IR spectra,spin splitting energies,excited states and UV/Vis absorption spectra were obtained.The structural parameters of the calculated isolated complex are in good agreement with the X-ray data.We investigate three dimers of [Fe(bapbpy)(NCS)2] complex for their magnetic properties.It has been found that the complex(1,3) has ferromagnetic character while the others are antiferromagnetic in nature by using a broken symmetry approach in the DFT framework(BS-DFT) with support from the coupling constant values(J) and spin density plots.
基金Supported by the National Natural Sciences Foundation of China
文摘The interaction of trivalent lanthanide ions and divalent calcium ions with sph-'ngomyelm bilayer has been studied by FT-Raman spectroscopy.The results showed that the bonding of metal ions to the phosphate group of sphingomyelin bi-iayer,either La3+or Ca2+did not change the conformation of the choline group,that is,O-C-C-N+is still in its gauche conformation.The presence of metal ions changed the states of the interfacial region from liquid-like to amorphous state and even to crystalline.They increased the fluidity of acyl chains of sphingomyelin bilaver and made them packed disorderly.
基金Project supported by the Science and Technology Research Project of Henan Province, China (Grant No. 172102210391)the Higher Vocational School Program for Key Teachers from Department of Education of Henan Province, China (Grant No. 2019GZGG042)。
文摘We execute the density functional theory(DFT) and time-dependent density functional theory(TDDFT) approaches to make a detailed exploration about excited state luminescent properties as well as excited state intramolecular proton transfer(ESIPT) mechanism for the novel 2,6-dimethyl phenyl(DMP-HBT-py) system. Firstly, we check and confirm the formation and stabilization of hydrogen bonding interaction for DMP-HBT-py. Via optimized geometrical parameters of primary chemical bond and infrared(IR) spectra, we find O–H··· N hydrogen bond of DMP-HBT-py should be strengthened in S1 state. Insights into frontier molecular orbitals(MOs) analyses, we infer charge redistribution and charge transfer(ICT)phenomena motivate ESIPT trend. Via probing into potential energy curves(PECs) in related electronic states, we come up with the ultrafast ESIPT behavior due to low potential barrier. Furthermore, we search the reaction transition state(TS)structure, the ultrafast ESIPT behavior and mechanism of DMP-HBT-py compound can be re-confirmed. We sincerely wish this work could play roles in further developing novel applications based on DMP-HBT-py compound and in promoting efficient solid emitters in OLEDs in future.
文摘The kinetic study of in-situ eopolymerization of aniline with o- and p-methylaniline by ammonium persulfate (APS) has been carried out. UV-vis spectroscopic method was used to investigate the course of copolymerization. Structural characterization was studied by PT-IR spectral analysis. The electronic spectra of the copolymers poly(aniline-co-p-toluidine) and poly(aniline-co-o- toluidine) show blue shift. The shift has been observed in the bands corresponding to π→π^* transition as well as in the exciton transition. The increase in absorbance recorded during the reaction for different concentration of aniline, o- and p-toluidine at various intervals of time of polymerization reaction indicates a growth in the polymer formation. The resulting first-order rate constant was used to calculate the rate of copolymer formation using the rate equation -d[A]/dt = kc^n.
基金the Science and Technology Research Program of Liaoning Province (No. 2005080)National Science and Technology Foundation of Liaoning Province (No. 20061047)
文摘The stable acetone molecule clusters have been studied by using Becke's threeparameter (B3LYP) density functional theory (DFT) with standard 6-31G(d) basis set. The calculated results show that the optimal structures of acetone clusters are cyclic and the cycles become larger and larger with the increase of cluster size. The strongest vibration peaks for neutral clusters are C=O stretching vibration. The C=O stretching peaks of cyclic acetone clusters split into double ones when n≥3, the frequencies are red-shifted and corresponding intensifies increase with the increase of cluster Size.
基金the National Natural Science Foundation of China(Grant No.10774039)the Development Program in Science and Technology of Henan Province(No.102300410114)Henan University of Science and Technology for Young Scholars(No.2009QN0032)for their support of this work.
文摘Quantum chemistry calculations have been performed using Gaussian03 program to compute optimized geometry,harmonic vibrational frequency along with intensities in IR and Raman spectra at RHF/6-31++G^(**)and B3LYP/6-31++G^(**)levels for phenobarbitone(C12H12N2O3)in the ground state.The scaled harmonic vibrational frequencies have been compared with experimental FT-IR and FT-Raman spectra.Theoretical vibrational spectra of the title compound were interpreted by means of potential energy distributions(PEDs)using MOLVIB program.A detailed interpretation of the infrared spectra of the title compound is reported.On the basis of the agreement between the calculated and observed results,the assignments of fundamental vibrational modes of phenobarbitone were examined and some assignments were proposed.The theoretical spectrograms for FT-IR and FT-Raman spectra of the title compound have been constructed.
基金Project supported by the Natural Science Foundation of Shandong Province(Nos.ZR2010CL011 and ZR2010BM033)
文摘The title molecule, 3-(4-(dimethylamino)benzylidene)-l,5-dioxaspiro[5.5] unde- cane-2,4-dione (I), was synthesized and characterized by elemental analysis, IR, UV-vis spectra and X-ray diffraction analysis. The compound belongs to the triclinic system, space group Pi with a = 6.3640(6), b = 7.7404(8), c = 16.2890(18) A, α = 86.860(2), β = 85.837(2), γ = 79.6720(10)°, V = 786.60(14) A3, D, = 1.331 g/cm3, and F(000) = 336. Geometrical structure of the title compound was optimized by density functional theory (DFT) using B3LYP method with 6-31G** as the basis set. The vibrational frequencies were calculated by the DFT method and the results are consistent with the observed frequencies. The electronic absorption spectra were studied with the time- dependent density functional theory (TD-DFT), showing the calculation results in good agreement with the corresponding experimental data.