A globla potential energy surface （PES） for the H＋CH4←→H2＋CH3 reaction has been constructed using the neural networks method based on 47783 high level ab initio geometry points. Extensive quasi-classical traject...A globla potential energy surface （PES） for the H＋CH4←→H2＋CH3 reaction has been constructed using the neural networks method based on 47783 high level ab initio geometry points. Extensive quasi-classical trajectories and quantum scattering calculations were carried out to check the convergence of the PES. This PES, fully converged with respect to the fitting procedure and the number of ab initio points, has a very small fitting error, and is much faster on evaluation than the modified Shepard interpolating PES, representing the best available PES for this benchmark polyatomic system.展开更多
Ab initio CCSD(T)/CBS//B3LYP/6-311G(d,p)calculations of the potential energy surface for possible dissociation channels of HOC2H3F,as well as Rice-Ramsperger-Kassel-Marcus(RRKM)calculations of rate constants,were carr...Ab initio CCSD(T)/CBS//B3LYP/6-311G(d,p)calculations of the potential energy surface for possible dissociation channels of HOC2H3F,as well as Rice-Ramsperger-Kassel-Marcus(RRKM)calculations of rate constants,were carried out,in order to predict statistical product branching ratios in dissociation of HOC2H3F at various internal energies.The most favorable reaction pathway leading to the major CH2CHO+HF products is as the following:OH+C2H3F→i2→TS14→i6→TS9→i3→TS3→CH2CHO+HF,where the rate-determining step is HF elimination from the CO bridging position via TS11,lying above the reactants by 3.8 kcal/mol.The CH2O+CH2F products can be formed by F atom migration from Cαto Cβposition via TS14,then H migration from O to Cαposition via TS16,and C-C breaking to form the products via TS5,which is 1.8 kcal/mol lower in energy than the reactants,and 4.0 kcal/mol lower than TS11.展开更多
The van der Waals (vdW) interaction is very important in fields of physics, biology and chemistry, and its role in reaction dynamics is an issue of great interest. In this review, we focus on the recent progresses in ...The van der Waals (vdW) interaction is very important in fields of physics, biology and chemistry, and its role in reaction dynamics is an issue of great interest. In this review, we focus on the recent progresses in the theoretical and experimental studies on the vdW interaction in bimolecular reactions. In particular, we review those studies that have advanced our understanding of how the vdW interaction can strongly influence the dynamics in both direct activated and complex-forming reactions, and further extend the discussion to the polyatomic reactions involving more atoms and those occurring at cold and ultracold temperatures. We indicate that an accurate description of the delicate vdW structure and long-range potential remains a challenge nowadays in either ab initio calculations or the fitting of the potential energy surfaces. We also present an explanation on the concept of vdW saddle proposed by us recently which may have general importance.展开更多
A new potential energy surface is presented for the triplet state 3At of the chemical reaction S（3P）＋H2 from a set of accurate ab initio data. The single point energies are computed using highly correlated complete...A new potential energy surface is presented for the triplet state 3At of the chemical reaction S（3P）＋H2 from a set of accurate ab initio data. The single point energies are computed using highly correlated complete active space self-consistent-field and multi-reference configuration interaction wave functions with a basis set of aug-cc-pV5Z. We have fitted the full set of energy values using many-body expansion method with an Aguado-Paniagua function. Based on the new potential energy surface, we carry out the time-dependent wave packet scattering calculations over the collision energy range of 0.8-2.2 eV. Both the centrifugalsudden approximation and Coriolis Coupling cross sections are obtained. In addition, the total reaction probabilities are calculated for the reactant H2 initially in the vibrational states v=0-3 （j=0）. It is found that initial vibrational excitation enhances the title reaction.展开更多
The reasonable dissociation limit for the G^1Ⅱg, state of dimer ^7Li2 is determined. The equilibrium internuclear distance, dissociation energy, harmonic frequency, vibrational zero energy, and adiabatic excitation e...The reasonable dissociation limit for the G^1Ⅱg, state of dimer ^7Li2 is determined. The equilibrium internuclear distance, dissociation energy, harmonic frequency, vibrational zero energy, and adiabatic excitation energy are calculated using a symmetry-adapted-cluster configuration-interactlon method in complete active space in Gaussian03 program package at such numerous basis sets as 6-311 ＋＋G, 6-311 ＋＋G（2df,2pd）, 6-311 ＋＋G（2df, p）, cc-PVTZ, 6- 311＋＋G（3df,3pd）, CEP-121G, 6-311＋＋G（2df, pd）, 6-311＋＋G（d,p）,6-311G（3df,3pd）, D95（3df,3pd）, 6-311＋＋G（3df,2p）, 6-311＋＋G（2df）, 6-311＋＋G（df, pd） D95V＋＋, and DGDZVP. The complete potential energy curves are obtained at these sets over a wide internuclear distance range and have least squares fitted to Murrell-Sorbie function. The conclnsion shows that the basis set 6-311＋＋G（2df, p） is a most suitable one for the G^1Ⅱg state. At this basis set, the calculated spectroscopic constants Te, De, Eo, Re, ωe, ωeXe, ae, and Be are of 3.9523 eV, 0.813 06 eV, 113.56 cm^-1, 0.320 15 nm, 227.96 cm^-1, 1.6928 cm^-1, 0.004 436 cm^-1, and 0.4689 cm^-1, respectively, which are in good agreement with measurements whenever available. The total 50 vibrational levels and corresponding inertial rotation constants are for the first time calculated and compared with available RKR data. And good agreement with measurements is obtained.展开更多
Different classes of first-principle pseudopotentials are compared and various schemes for pseudopotential generation based on norm conservation are discussed in this paper. BHS (Bachelet, Hamann, and Schlüter)-...Different classes of first-principle pseudopotentials are compared and various schemes for pseudopotential generation based on norm conservation are discussed in this paper. BHS (Bachelet, Hamann, and Schlüter)-scheme and V (Vanderbilt)-modifications are used to derive the KB (Kleinman and Bylander)-pseudopotentials and pseudo wave functions of bismuth. Quality test of pseudopotentials shows that no ghost states occur in the logarithmic der ivatives of pseudo wave functions of Bismuth. The obtained bond length of bismuth dimer with this type of pseudopotentials is in good agreement with previous accurately calculate d ab initio quantum chemical result.展开更多
In the current economic development, the competitiveness of the traditional pattern is backward, so under the background of the high-end equipment manufacturing industry development facing of great pressure, how to ob...In the current economic development, the competitiveness of the traditional pattern is backward, so under the background of the high-end equipment manufacturing industry development facing of great pressure, how to obtain new competitive power to achieve sustained competitive advantage, how to develop from equipment manufacturing power to the development of equipment manufacturing power becomes the focus of the present. In this paper, based on talent accumulation effect, then analysis the advantages of high-end equipment manufacturing industry talents converging forces and its access to obtain talent agglomeration competitiveness.展开更多
基金V. ACKNOWLEDGEMENTS This work was supported by the National Natural Science Foundation of China （No.90921014）, the Chinese Academy of Sciences, and the Ministry of Science and Technology of China （No.2013CB834601）.
文摘A globla potential energy surface （PES） for the H＋CH4←→H2＋CH3 reaction has been constructed using the neural networks method based on 47783 high level ab initio geometry points. Extensive quasi-classical trajectories and quantum scattering calculations were carried out to check the convergence of the PES. This PES, fully converged with respect to the fitting procedure and the number of ab initio points, has a very small fitting error, and is much faster on evaluation than the modified Shepard interpolating PES, representing the best available PES for this benchmark polyatomic system.
基金supported by the National Natural Science Foundation of China (No.91641116).
文摘Ab initio CCSD(T)/CBS//B3LYP/6-311G(d,p)calculations of the potential energy surface for possible dissociation channels of HOC2H3F,as well as Rice-Ramsperger-Kassel-Marcus(RRKM)calculations of rate constants,were carried out,in order to predict statistical product branching ratios in dissociation of HOC2H3F at various internal energies.The most favorable reaction pathway leading to the major CH2CHO+HF products is as the following:OH+C2H3F→i2→TS14→i6→TS9→i3→TS3→CH2CHO+HF,where the rate-determining step is HF elimination from the CO bridging position via TS11,lying above the reactants by 3.8 kcal/mol.The CH2O+CH2F products can be formed by F atom migration from Cαto Cβposition via TS14,then H migration from O to Cαposition via TS16,and C-C breaking to form the products via TS5,which is 1.8 kcal/mol lower in energy than the reactants,and 4.0 kcal/mol lower than TS11.
基金supported by the National Natural Science Foundation of China (No.21773251 and No.91741106)the Beijing National Laboratory for Molecular Sciences and Chinese Academy of Sciences
文摘The van der Waals (vdW) interaction is very important in fields of physics, biology and chemistry, and its role in reaction dynamics is an issue of great interest. In this review, we focus on the recent progresses in the theoretical and experimental studies on the vdW interaction in bimolecular reactions. In particular, we review those studies that have advanced our understanding of how the vdW interaction can strongly influence the dynamics in both direct activated and complex-forming reactions, and further extend the discussion to the polyatomic reactions involving more atoms and those occurring at cold and ultracold temperatures. We indicate that an accurate description of the delicate vdW structure and long-range potential remains a challenge nowadays in either ab initio calculations or the fitting of the potential energy surfaces. We also present an explanation on the concept of vdW saddle proposed by us recently which may have general importance.
文摘A new potential energy surface is presented for the triplet state 3At of the chemical reaction S（3P）＋H2 from a set of accurate ab initio data. The single point energies are computed using highly correlated complete active space self-consistent-field and multi-reference configuration interaction wave functions with a basis set of aug-cc-pV5Z. We have fitted the full set of energy values using many-body expansion method with an Aguado-Paniagua function. Based on the new potential energy surface, we carry out the time-dependent wave packet scattering calculations over the collision energy range of 0.8-2.2 eV. Both the centrifugalsudden approximation and Coriolis Coupling cross sections are obtained. In addition, the total reaction probabilities are calculated for the reactant H2 initially in the vibrational states v=0-3 （j=0）. It is found that initial vibrational excitation enhances the title reaction.
基金The project supported by National Natural Science Foundation of China under Grant No. 10574039
文摘The reasonable dissociation limit for the G^1Ⅱg, state of dimer ^7Li2 is determined. The equilibrium internuclear distance, dissociation energy, harmonic frequency, vibrational zero energy, and adiabatic excitation energy are calculated using a symmetry-adapted-cluster configuration-interactlon method in complete active space in Gaussian03 program package at such numerous basis sets as 6-311 ＋＋G, 6-311 ＋＋G（2df,2pd）, 6-311 ＋＋G（2df, p）, cc-PVTZ, 6- 311＋＋G（3df,3pd）, CEP-121G, 6-311＋＋G（2df, pd）, 6-311＋＋G（d,p）,6-311G（3df,3pd）, D95（3df,3pd）, 6-311＋＋G（3df,2p）, 6-311＋＋G（2df）, 6-311＋＋G（df, pd） D95V＋＋, and DGDZVP. The complete potential energy curves are obtained at these sets over a wide internuclear distance range and have least squares fitted to Murrell-Sorbie function. The conclnsion shows that the basis set 6-311＋＋G（2df, p） is a most suitable one for the G^1Ⅱg state. At this basis set, the calculated spectroscopic constants Te, De, Eo, Re, ωe, ωeXe, ae, and Be are of 3.9523 eV, 0.813 06 eV, 113.56 cm^-1, 0.320 15 nm, 227.96 cm^-1, 1.6928 cm^-1, 0.004 436 cm^-1, and 0.4689 cm^-1, respectively, which are in good agreement with measurements whenever available. The total 50 vibrational levels and corresponding inertial rotation constants are for the first time calculated and compared with available RKR data. And good agreement with measurements is obtained.
文摘Different classes of first-principle pseudopotentials are compared and various schemes for pseudopotential generation based on norm conservation are discussed in this paper. BHS (Bachelet, Hamann, and Schlüter)-scheme and V (Vanderbilt)-modifications are used to derive the KB (Kleinman and Bylander)-pseudopotentials and pseudo wave functions of bismuth. Quality test of pseudopotentials shows that no ghost states occur in the logarithmic der ivatives of pseudo wave functions of Bismuth. The obtained bond length of bismuth dimer with this type of pseudopotentials is in good agreement with previous accurately calculate d ab initio quantum chemical result.
文摘In the current economic development, the competitiveness of the traditional pattern is backward, so under the background of the high-end equipment manufacturing industry development facing of great pressure, how to obtain new competitive power to achieve sustained competitive advantage, how to develop from equipment manufacturing power to the development of equipment manufacturing power becomes the focus of the present. In this paper, based on talent accumulation effect, then analysis the advantages of high-end equipment manufacturing industry talents converging forces and its access to obtain talent agglomeration competitiveness.
