Ab initio calculation of the ground and first excited states of the lithium dimer

JianJun Qi,YuYao Bai,QianQian Guo,Yong-Chang Han,Maksim B Shundalau

Table 1. The fitting parameters of the MS analytical potential energy functions for the ${\rm{X}}{}^{{\rm{1}}}{\rm{\Sigma }}_{g}^{+}$ state based on MRCI/AVXZ (X = T, Q, 5) and the ${\rm{A}}{}^{{\rm{1}}}{\rm{\Sigma }}_{u}^{+}$ state based on MRCI/AV5Z. The corresponding ab initio calculation values for Re and De are listed in the parentheses.

Potential parameters AVTZ ${\rm{X}}{}^{{\rm{1}}}{\rm{\Sigma }}_{g}^{+}$ AVQZ ${\rm{X}}{}^{{\rm{1}}}{\rm{\Sigma }}_{g}^{+}$ AV5Z ${\rm{X}}{}^{{\rm{1}}}{\rm{\Sigma }}_{g}^{+}$ AV5Z ${\rm{A}}{}^{{\rm{1}}}{\rm{\Sigma }}_{u}^{+}$ Re/Å 2.6994 (2.6989) 2.6976 (2.6978) 2.6974 (2.6977) 3.1421 (3.1401) De/cm−1 8337.5346 (8338.6302) 8414.9678 (8416.1149) 8428.0893 (8429.2647) 9291.0809 (9290.2886) a1/Å−1 2.1776 2.1742 2.1729 1.5266 a2/Å−2 1.6309 1.6239 1.6214 0.8087 a3/Å−3 0.6373 0.6320 0.6305 0.2635 a4/Å−4 0.1171 0.1149 0.1146 0.05164 a5/Å−5 −0.027 57 −0.028 35 −0.028 30 0.009 509 a6/Å−6 −0.014 67 −0.014 37 −0.014 34 0.000 7928 a7/Å−7 0.002 564 0.002 635 0.002 566 −0.002 086 a8/Å−8 0.001 453 0.001 395 0.001 388 0.000 1562 a9/Å−9 0.000 1205 0.000 1292 0.000 1395 0.000 2391 a10/Å−10 −0.000 1254 −0.000 1253 −0.000 1269 −0.000 050 66 a11/Å−11 0.000 013 69 0.000 013 57 0.000 013 62 0.000 003 274 RMS/cm−1 0.7672 0.8006 0.8166 2.7880