An analytic expression of the potential energy surface(PES) of the ground state of the Ne-HF complex is obtained by utilizing nonlinear least square method to fit the intermolecular interaction energies [Zhang Y. Guiz...An analytic expression of the potential energy surface(PES) of the ground state of the Ne-HF complex is obtained by utilizing nonlinear least square method to fit the intermolecular interaction energies [Zhang Y. Guizhou Science,2003,21(3):9-13(in Chinese)],which have been computed using the augmented correlation-consistent polarized quadruple zeta basis set aug-cc-pVQZ at the theoretical level of CCSD(T). On the basis of the PES,the partial cross sections(PCSs) at the incident energies of 60,75,100 and 150 meV for collisions between Ne atoms and HF molecules are calculated using the quantum close coupling approach. The effects of the long-range attractive and the short-range anisotropic interactions on the inelastic PCSs are discussed in detail. The results show:(1) The long-range attractive well of the EPS makes the significant contribution to the lower excitation PCSs,especially the tail maximum for j = 0→j′ = 1 transitions,whereas no contribution is to the j′≥3 inelastic transitions.(2) The short-range(the repulsive and attractive) interaction makes the significant contri-bution to the lower excitation PCSs,especially the main peak for j = 0→j′ = 1,2. As for the transitions of j′≥3,the short-range interaction plays a key role in the inelastic excitation.(3) Although the positions of the maximums and minimums of the inelastic PCSs are different at the collision energies,they correspond to almost the same impact parameter.展开更多
We investigate the elastic and thermodynamic properties of nanolaminate VzA1C by using the ab initio pseudopotential total energy method. The axial compressibility shows that the c axis is always stiffer than a axis. ...We investigate the elastic and thermodynamic properties of nanolaminate VzA1C by using the ab initio pseudopotential total energy method. The axial compressibility shows that the c axis is always stiffer than a axis. The elastic constants revealed the structural instability at about 500 and 732 GPa. Furthermore, elastic constants C44 reached its maximum at about 550 GPa, dif- fering with the other four C^1, G2, C13 and 6＂33 constants. The Poisson＇s ratio investigations demonstrated that a higher ionic or weaker covalent contribution in intra-atomic bonding and the degree of ionicity increases with pressure. The G/B and B]C44 investigations revealed that VzAIC is brittle and the brittleness decreases with pressure. Also, we found that V2A1C is elastic anisotropic materials and the degree of anisotropy rapidly rises with pressure. Study on Debye temperature and Grtineisen pa- rameter observed weak temperature and strong pressure responses, whereas the sensitive dependence in the thermal expansion coefficient and Helmholtz free energy are clearly seen.展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos. 10676025 and 10574096)
文摘An analytic expression of the potential energy surface(PES) of the ground state of the Ne-HF complex is obtained by utilizing nonlinear least square method to fit the intermolecular interaction energies [Zhang Y. Guizhou Science,2003,21(3):9-13(in Chinese)],which have been computed using the augmented correlation-consistent polarized quadruple zeta basis set aug-cc-pVQZ at the theoretical level of CCSD(T). On the basis of the PES,the partial cross sections(PCSs) at the incident energies of 60,75,100 and 150 meV for collisions between Ne atoms and HF molecules are calculated using the quantum close coupling approach. The effects of the long-range attractive and the short-range anisotropic interactions on the inelastic PCSs are discussed in detail. The results show:(1) The long-range attractive well of the EPS makes the significant contribution to the lower excitation PCSs,especially the tail maximum for j = 0→j′ = 1 transitions,whereas no contribution is to the j′≥3 inelastic transitions.(2) The short-range(the repulsive and attractive) interaction makes the significant contri-bution to the lower excitation PCSs,especially the main peak for j = 0→j′ = 1,2. As for the transitions of j′≥3,the short-range interaction plays a key role in the inelastic excitation.(3) Although the positions of the maximums and minimums of the inelastic PCSs are different at the collision energies,they correspond to almost the same impact parameter.
基金supported by the National Natural Science Foundation of China (Grant Nos.10974139,10964002,11104247 and 11176020)the Provincial Natural Science Foundation of Guizhou (Grant Nos.[2009]2066 and TZJF-2008-42)+2 种基金the Provincial Natural Science Foundation of Hainan (Grant No.110001)the Provincial Natural Science Foundation of Chong Qing(Grant No.CSTCcstc2011jja90002)the Provincial Natural Science Foundation of Zhejiang (Grant No.Y201121807)
文摘We investigate the elastic and thermodynamic properties of nanolaminate VzA1C by using the ab initio pseudopotential total energy method. The axial compressibility shows that the c axis is always stiffer than a axis. The elastic constants revealed the structural instability at about 500 and 732 GPa. Furthermore, elastic constants C44 reached its maximum at about 550 GPa, dif- fering with the other four C^1, G2, C13 and 6＂33 constants. The Poisson＇s ratio investigations demonstrated that a higher ionic or weaker covalent contribution in intra-atomic bonding and the degree of ionicity increases with pressure. The G/B and B]C44 investigations revealed that VzAIC is brittle and the brittleness decreases with pressure. Also, we found that V2A1C is elastic anisotropic materials and the degree of anisotropy rapidly rises with pressure. Study on Debye temperature and Grtineisen pa- rameter observed weak temperature and strong pressure responses, whereas the sensitive dependence in the thermal expansion coefficient and Helmholtz free energy are clearly seen.
