%A Zhang Li, Zhu Zheng-He
%T Full relativistic calculations of the quadrupole and electric field gradients for C_{2}, N_{2}, and O_{2}
%0 Journal Article
%D 2013
%J Chin. Phys. B
%R 10.1088/1674-1056/22/2/023102
%P 23102-023102
%V 22
%N 2
%U {http://cpb.iphy.ac.cn/CN/abstract/article_52176.shtml}
%8 2013-01-01
%X In the present work we calculate the energies, quadrupole moments, and electric field gradients (EFGs) of molecules C_{2}, N_{2}, and O_{2} based on DIRRCI method with basis aug-cc-pVTZ-DK. We prove that the quadratic force constant *k*_{2} is the product of charge and EFG at its equilibrium nuclear distance. The dipole charge distributions for these symmetrical molecules are all in equilibrium, however, the quadrupole charge distributions are far from equilibrium, among these, there is the most remarkable deviation from equilibrium for N_{2}, for its many charges concentrate on two sides of molecule, which is in agreement with the well-known characteristic of nitrogen molecule. The relativistic effect is remarkable even for the same period.