Theoretical study of the N—H···O red-shifted andblue-shifted hydrogen bonds

Theoretical calculations are performed to study the nature of the hydrogen bonds in complexes HCHO···HNO, HCOOH···HNO, HCHO···NH3, HCOOH···NH3, HCHO···NH2F and HCOOH···NH2F. The geomet- ric structures and vibrational frequencies of these six complexes at the MP2/6-31+G(d,p), MP2/6-311++G(d,p), B3LYP/6-31+G(d,p) and B3LYP/6-311++G(d,p) levels are calculated by standard and counterpoise-corrected methods, respectively. The results indicate that in complexes HCHO···HNO and HCOOH···HNO the N—H bond is strongly contracted and N—H···O blue-shifted hydrogen bonds are observed. While in complexes HCHO···NH3, HCOOH···NH3, HCHO···NH2F and HCOOH···NH2F, the N—H bond is elongated and N—H···O red-shifted hydrogen bonds are found. From the natural bond orbital analysis it can be seen that the X—H bond length in the X—H···Y hydrogen bond is controlled by a balance of four main factors in the opposite directions: hyperconjugation, electron density redistribu- tion, rehybridization and structural reorganization. Among them hyperconjugation has the effect of elongating the X—H bond, and the other three factors belong to the bond shortening effects. In complexes HCHO···HNO and HCOOH···HNO, the shortening effects dominate which lead to the blue shift of the N—H stretching frequencies. In complexes HCHO···NH3, HCOOH···NH3, HCHO···NH2F and HCOOH···NH2F where elongating effects are dominant, the N—H···O hydrogen bonds are red-shifted.

Assembly Induced Super-Large Red-Shifted Absorption:The Burgeoning Field of Organic Near-Infrared Materials

Supramolecular assembly of organic dye compounds with J-aggregation leads to a red-shifted absorption spectrum that greatly facilitates the construction of near-infrared(NIR)materials.A considerable improvement of the material functions requires that the absorption red-shift be larger than 100 nm,but such a super-large red-shift is challenging,and the rules leading to the super-large red-shifted absorption is still not explicit.In this review,we focused on those J-aggregated organic dye materials with super-large red-shifted absorption.The nature of the super-large red-shift is originated fromthe intermolecular charge transfer between neighboring chromophores.The super-large red-shift can be obtained by tuning either the molecular structure or kinetic assembly process in a delicate manner.Materials with super-large red-shifted absorption have been successfully applied to biological imaging,phototherapy,electronic devices,and solar cells,and show great potential in many other fields.The elaboration of assembly induced super-large red-shifted absorption is promising for design of supramolecular NIR materials with tuned structures,enhanced functionalities,and a wide array of applications.

Computed Tidal Relativistic Red-Shifts of Frequency Standards on Earth and in Space Stations

Frequencies of frequency standards are shifted by the local static gravity red shifts and also modulated by the tidal relativistic red shifts. We compute the tidal relativistic red shifts using a time-domain method and present the numerical results for the National Institute of Metrology （NIM） in Beijing, Laboratoire National de Metrologie et Essais-Systeme de References Temps-Espaee （LNE-SYRTE） in Paris and Physikalisch-Teehnische Bundesanstalt （PTB） in Braunschweig. The differences of the tidal relativistic red shift approach as large as 1.1 × 10^-16 when frequency standards at NIM are compared with those at SYRTE and PTB. Moreover, the tidal relativistic red shifts of frequency standards in space stations are also computed.

Using of the Generalized Special Relativity in Deriving the Equation of the Gravitational Red-Shift

In this work we present a study of a new method to prove the equation of the gravitational red shift of spec-tral lines. That’s according to the generalized special relativity theory. The equation of the gravitational red shift of spectral lines has been studied in many different works, using different methods depending on the Newtonian mechanics, and other theories. Although attention was drawn to the fact that the well-known ex-pression of the gravitational Red-Shift of spectral lines may be derived with no recourse to the general rela-tivity theory! In this study a unique derivation has been done using the Generalized Special Relativity (GSR) and the same result obtained.

Thickness Dependent Behavior of Photoluminescence of Tris(8-hydroxyquinoline)Aluminum Film

In situ thickness dependent photoluminescence （PL） measurements of tris（8-hydroxyquinoline） aluminum（Alq3） film were performed. At the beginning of Alq3 deposition on the glass substrate, the Alq3 emission showed a sharp red-shift. Further deposition of Alq3 resulted slight red-shift, and finally tended to saturated value. The total red-shift of about 12 nm was observed for the Alq3 film thickness range from 2 to 500 nm.This red-shift was attributed to the change from the 2D to 3D exciton state with increasing Alq3 film thickness. Meanwhile, the PL intensity of Alq3 emission increased continuously, and showed a rate change at the initial deposition of Alq3 due to non-rediative decay of excitons arised from the interaction between excitons and the substrate, and finally tended to saturation with the Alq3 thickness.

Bismuth-content-dependent polarized Raman spectrum of InPBi alloy

We systematically investigate the optical properties of the InP1-xBix ternary alloys with 0≤x≤2.46%,by using high resolution polarized Raman scattering measurement.Both InP-like and InBi-like optical vibration modes（LO） are identified in all the samples,suggesting that most of the Bi-atoms are incorporated into the lattice sites to substitute Patoms.And the intensity of the InBi-like Raman mode is positively proportional to the Bi-content.Linear red-shift of the InP-like longitudinal optical vibration mode is observed to be 1.1 cm-1/Bi%,while that of the InP-like optical vibration overtone（2LO） is nearly doubled.In addition,through comparing the（XX） and Z（XY） Raman spectra,longitudinaloptical-plasmon-coupled（LOPC） modes are identified in all the samples,and their intensities are found to be proportional to the electron concentrations.

Power dependence of terahertz carrier frequency in a plasma-based two-color generation process

We conduct a frequency spectrum experiment to investigate terahertz（THz） emissions from laser-induced air plasma under different laser incident powers. The frequency spectra are measured using both air-biased-coherent detection and a Michelson interferometer. The red-shift of the THz pulse carrier frequency is observed as a response to increased pump power. These phenomena are related to plasma collisions and can be explained by the plasma collision model. Based on these findings, it is apparent that the tuning of the THz carrier frequency can be achieved through regulation of the pump beam.

Generalized general and special relativity in the presence of the gravitation, related to the space-time curvature

Using the equation of motion expression in a curved space proper time is a useful method to explain the relation between the curvature of space-time and the potential of any field obtained. Taking into account the expression for the Hamiltonian density, the effect of fields, as well as the effect motion, on the mass, and, their effect on energy is found. The new expression of energy reduced to the ordinary Newton’s energy expression. It also explains the gravitational red shift.

Effects of Heat Treatment on Thermoelectric and Infrared Properties of Bi_2Te_3 Films

In this work,Bi2Te3 films（250 nm） are fabricated on Si O2/Si substrates by radio frequency（RF） magnetron sputtering at room temperature,and the prepared films are annealed over the temperature range of 200 °C to 400 °C.Crystallinity and electrical properties of the films can be tuned correspondingly.The power factors of Bi2Te3 films of 0.85 μW/K2 cm to 11.43 μW/K2 cm were achieved after annealing.The infrared reflectance measurements from 2.5 μm to 5.0 μm demonstrate that there is also a slight red-shift of the plasma oscillation frequency in the Bi2Te3 films.By means of plasmonic calculations,we attribute the red-shift of absorption peaks to the reduction of carrier concentration and the change of effective mass of Bi2Te3 films with the increased annealing temperature.

Riemannian Space-Time, de Donder Conditions and Gravitational Field in Flat Space-Time

Let the coordinate system xi of flat space-time to absorb a second rank tensor field Φij of the flat space-time deforming into a Riemannian space-time, namely, the tensor field Φuv is regarded as a metric tensor with respect to the coordinate system xu. After done this, xu is not the coordinate system of flat space-time anymore, but is the coordinate system of the new Riemannian space-time. The inverse operation also can be done. According to these notions, the concepts of the absorption operation and the desorption operation are proposed. These notions are actually compatible with Einstein’s equivalence principle. By using these concepts, the relationships of the Riemannian space-time, the de Donder conditions and the gravitational field in flat space-time are analyzed and elaborated. The essential significance of the de Donder conditions (the harmonic conditions or gauge) is to desorb the tensor field of gravitation from the Riemannian space-time to the Minkowski space-time with the Cartesian coordinates. Einstein equations with de Donder conditions can be solved in flat space-time. Base on Fock’s works, the equations of gravitational field in flat space-time are obtained, and the tensor expression of the energy-momentum of gravitational field is found. They all satisfy the global Lorentz covariance.

Newton’s and Einstein’s Gravity in a New Perspective for Planck Masses and Smaller Sized Objects

Here we derive Newton’s and Einstein’s gravitational results for any mass less than or equal to a Planck mass. All of the new formulas presented in this paper give the same numerical output as the traditional formulas. However, they have been rewritten in a way that gives a new perspective on the formulas when working with gravity at the level of the subatomic world. To rewrite the well-known formulas in this way could make it easier to understand the strengths and weaknesses in Newton’s and Einstein’s gravitation formulas at the subatomic scale, potentially opening them up for new important interpretations and extensions. For example, we suggest that the speed of gravity equal to that of light is actually embedded and hidden inside of Newton’s gravitational formula.

Non-parabolic effect for femtosecond laser-induced ultrafast electro-absorption in solids

A theoretical study for femtosecond laser-induced ultrafast electro-absorption of bulk solids is presented.Our numerical results show that,in the case of low intensity of the pump laser where the interaction between the pump laser and solids is in the multi-photon regime,the energy band of solids can be approximately taken as a parabolic band and electro-absorption spectrums from the parabolic band and real band are nearly the same.While,in the case of high intensity where the interaction is in the tunneling regime,spectrums from the parabolic band and real band are quite different.The physical mechanism for the difference in the tunneling regime is found.We find that the non-parabolic parts of the real energy band and Bragger scattering of electrons near the first Brillouin zone boundaries,which are neglected in previous studies,strongly influence the electro-absorption spectrum in the tunneling regime.These two physical processes cause the difference of spectrums.Our theoretical results are in accordance with the experiment result.

The Unusual Spectrum of the Mixture of Tin-octabutoxy Naphthalocyanine and SnCl_2 in CH_2Cl_2

The Q-band position of tin-centered 5, 9, 14, 18, 23, 27, 32, 36-octabutoxy 2, 3- phthalocyanine(SnNc(OBu)8) exhibits dramatic red-shift as mixed with SnCl2 in CH2Cl2.

Optical Properties of Silicon-doped InGaN and GaN Layers

The optical properties of Silicon-doped InGaN and GaN grown on sapphire by MOCVD have been investigated by photoluminescence (PL) method. At room temperature, the band-gap peak of InGaN is 437.0 nm and its full width of half-maximum (FWHM) is about 14.3 nm. The band-gap peak and FWHM for GaN are 364.4 nm and 9.5 nm, respectively. By changing the temperature from 20 K to 293 K, it is found that the PL intensity of samples decreases but the FWHM broadens with the increasing of the temperature. GaN sample shows red-shift, InGaN sample shows red-blue-red-shift. The temperature dependence of peak energy shift is studied and explained.

Theoretical Studies on the Intermonomer Interaction of F^(-)·(H_(2)O)_(n)(n=1,2)

Five optimized geometries of F-?(H2O)n (n = 1, 2) were obtained with ab initio calculation at the B3LYP/6-311++G** level. The accurate intermonomer interaction energy was calculated using the MP2 electron correlation correction as well as the basis set superposition error correction by the Boys-Bernardi “counterpoise” protocol. Natural bond orbital (NBO) theory was applied to quantify the relative strength of these interactions and account for their effects on the stability, structural and vibrational parameters of Fˉ?(H2O)n (n = 1, 2). It is shown that the charge transferring from the lone pair of F-1 to the σ?OH(…F) antibonding orbital is important. The results indicate the occupancy of σ?OH(…F) is increased (denoted ?σ?OH(…F)) and the σOH(…F) bond is leng- thened (denoted ?ROH(…F)), leading to the red-shift and the red-shift values have linear correlation with both ?σ?OH(…F) and ?ROH(…F).

The Optical Properties of Gravity

The resemblance between the equation for a characteristic hypersurface through which wavefronts of light rays pass and optical metrics of general relativity has long been known. Discontinuities in the hypersurface are due to refraction involving Snell’s law, as opposed to discontinuities in time that would involve the Doppler effect. The presence of a static gravitational potential in the metric coefficients is accounted by an index of refraction that is entirely dependent on the space coordinates. The two-time Einstein metric must be reinterpreted as a two-space scale metric because of the two different speeds of light. It is shown that the Schwarzschild metric is incompatible with the laws of classical physics. Gravitational waves are identified with the transverse-trans-verse plane wave solutions to Einstein’s equations in vacuum, which propagate at the speed of light. Yet, when energy loss is evaluated, his equations acquire, surprisingly, a source term. Poynting’s vector, which is not a true vector, is defined in terms of the pseudo-gravitational tensor, and hence energy is neither localizable nor conserved. The solutions to the equations of motion are geodesics and, by definition, do not radiate. A finite speed of propagation implies that gravitational waves should aberrate, like their electromagnetic wave counterparts, and if they do not aberrate they cannot radiate.

Luminescence of coelenterazine derivatives with C-8 extended electronic conjugation

Replacement of the methylene group at the C-8 position with an extended electronic conjugation is a new promising method to develop red-shifted coelenterazine derivatives. In this paper, we have described an oxygen-containing coelenterazine derivative with a significant red-shifted（63 nm）bioluminescence signal maximum relative to coelenterazine 400a（Deep Blue C^（TM）, 1）. In cell imaging, the sulfur-containing coelenterazine derivative displayed a significantly（1.77 ± 0.09;P≤0.01） higher luminescence signal compared to coelenterazine 400 a and the oxygen-containing coelenterazine derivative exhibited a slightly（0.74 ± 0.08; P≤0.05） lower luminescence signal. It is beneficial to understand further the underlying mechanisms of bioluminescence.

Core engineering of paired core-shell silver nanoclusters

Unlike the facile modulation of surface structure through protecting ligands,the core shielded by outer shell of silver nanoclusters is still hard to be controlled.Ligand effects may seep into the incipient growth of silver core.However,the comparable cases to validate such hypothesis are currently lacking.Herein,we shed light on two core-shell silver nanoclusters,Ag_(7)S_(6)@Ag_(48)(SD/Ag55b,SD=SunDi)and Ag_(6)S_(6)@Ag_(48)(SD/Ag54b),differing in only one silver atom in the core which varies from a pentagon-bipyramidal Ag_(7)to an octahedral Ag_(6)while keeping the Ag_(48)shielding shell almost the same.Although no direct bonding between alkynes and silver core is observed in them,we propose that the ligand effect still exerts profound influences on the size and geometry of silver core.The solution behaviours and complete ligand-exchange reaction of SD/Ag55b in CH_(2)Cl_(2)are investigated using electrospray ionization mass spectrometry.Due to more and stronger argentophilic interactions,SD/Ag55b exhibits room-temperature phosphorescence with a 40 nm red-shift compared to that of SD/Ag54b in CH_(2)Cl_(2).This work not only presents effective fabrication of silver nanoclusters via synergism of dithiophosphate and alkyne ligands,but also provides us a pair of comparable examples to understand substitution group effect of protecting ligand on the core structures and properties.

Theoretical Study on N-H…O Blue-shifted H-Bond for HNO…H2O2 Complex

A theoretical study on the blue-shifted H-bond N-H…O and red-shifted H-bond O-H…O in the complex HNO…H2O2 was conducted by employment of both standard and counterpoise-corrected methods to calculate the geometric structures and vibrational frequencies at the MP2/6-31G（d）, MP2/6-31 ＋ G（d,p）, MP2/6-311 ＋ ＋ G（d,p）, B3LYP/6-31G（d）, B3LYP/6-31 ＋G（d,p） and B3LYP/6-311 ＋ ＋G（d,p） levels. In the H-bond N-H…O, the calculated blue shift of N-H stretching frequency is in the vicinity of 120 cm^-1 and this is indeed the largest theoretical estimate of a blue shift in the X-H…Y H-bond ever reported in the literature. From the natural bond orbital analysis, the red-shifted H-bond O-H…O can be explained on the basis of the dominant role of the hyperconjugation. For the blue-shifted H-bond N-H…O, the hyperconjugation was inhibited due to the existence of significant electron density redistribution effect, and the large blue shift of the N-H stretching frequency was prominently due to the rehybridization of spn N-H hybrid orbital.

Synthesis and characterization of nano-sized YAG:Ce,Sm spherical phosphors

YAG：Ce,Sm spherical phosphors were synthesized by malic acid sol-gel method. The formation process of crystalline was characterized by X-ray diffraction （XRD） technique. The influence of Sm3＋ doping on the luminescent intensity and the morphology of phosphors were studied by fluorescence spectrum and scanning electron microscopy （SEM） techniques, respectively. The results indicated that the size of spherical powders was about 100 um calcined at 1200 ℃ for 3 h. The emission spectra of phosphors showed gradual red-shift from 525 to 540 um with the increase of doping concentration of Sm3＋ ion. A broadband emission specmtm of Ce3＋ ion appeared at 540 nm, and a series of emission peaks corresponding to the 4Gs/2-＋6Hd transition of Sm3＋ ion also appeared at 617 um with the doping of Sm3＋. The red component of YAG：Ce phosphors increased with the doping of Sm3＋.