物理化学学报 >> 2000, Vol. 16 >> Issue (11): 972-980.doi: 10.3866/PKU.WHXB20001104

研究论文 上一篇    下一篇

几种含芯电子相关能修正的G2和G2(ACI)方法

苏克和, 魏俊, 胡小玲, 岳红, 吕玲, 王育彬, 文振翼   

  1. 西北工业大学化工系 西安 710072|西北大学现代物理所 西安 710068
  • 收稿日期:2000-02-21 修回日期:2000-04-13 发布日期:2000-11-15
  • 通讯作者: 苏克和 E-mail:sukehe@nwpu.edu.cn

Core Electronic Correlation Modifications to G2 and G2(QCL) Theories

Su Ke-He, Wei Jun, Hu Xiao-Ling, Yue Hong, Lv Ling, Wang Yu-Bin, Wen Zhen-Yi   

  1. Departiment of Chemical Engineering,Northwestem Polytechnical Unicerstiy,Xi'an,Shaanxi 710072|Institute of Modern Physics,Northwest Unicersity,Xi'an,Shaanxi 710068
  • Received:2000-02-21 Revised:2000-04-13 Published:2000-11-15
  • Contact: Su Ke-He E-mail:sukehe@nwpu.edu.cn

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摘要：

针对冻结芯电子近似，在MP2/6-311G(d,p)级别上对G2、MP2/6-311G(d)和MP2/6-311G(d,p)级别上对G2(QCI)方法进一步考虑了芯电子相关能修正，尝试建立了G2(fu2)、G2(QCI/ful)和G2(QCI/fu2)方法。G2-l test set 的反应能量计算结果表明，这些方法进一步减小了经验修正量；G2(QCI/ful)和G2(QCI/fu2)也比G2(QCI)的总体精度有所提高；但G2(fu2)在G2基础上，总体精度没有改善。G2(fu2)、G2(QCI/ful)和G2(QCI/fu2)计算G2-l test set反应能量的平均绝对偏差分别为5.11、4.74和4.81kJ mol-1,G2和G2(QCI)分别为5.09和4.97kJ mol-1.

关键词: G2理论, G2(QCI)理论, 芯电子相光能, G2(fu2), G2(QCI/ful), G2(QCI/fu2)

Abstract:

In addition to our previous work of G2(ful) in Ref.[8],we proposed a further core electronic correlation modifieation at MP2/6-31G(d) level to G2(QCI),namely G2(QCI/ful),and that at MP2/6-311G(d,p) level to G2 and G2(QCI) theories,namely G2(fu2) and G2(QCI/fu2).The latter would need no additional calculation if the geometry is optimized at MP2(full)/6-311G(d,p) level/The modification energies,ΔE(fu2),were calculated via eq. ΔE(ful)=E[MP2](full)/6-31G(d)]-E[MP2(FC)/6-31G(d)] ΔE(fu2)=E[MP2](fu2)/6-311G(d,p)]-E[MP2(FC)/6-311G(d,p)] G2 and G2(QCI) theories were modified via eq. E[G2(fu2)]=E(G2)=ΔE(fu2)-HLC(G2)=HLC[G2(fu2)] E[G2(QCI/ful)]=E[G2(QCI)]+ΔE(ful)-HLC[G2(QCI)]+HLC[G2(QCI/ful)] E[G2(QCI/fu2)]=E[G2(QCI)]+ΔE(fu2)-HLC[G2(QCI)]+HLC[G2(QCI/fu2)] where, HLC[G2(fu2)]=-0.19nα-4.32nβ HLC[G2(QCI/ful)]=-0.19nα-4.77nβ HLC[G2(QCI/fu2)]=-0.19nα-4.65nβ It has been shown that the empirical High-Level-Correction(HLC) to either of the original G2 or G2(QCI) theory was reduced.G2(fu2) did not improve the over-all accuracy for the 125 G2-l test set reaction energies,however both G2(QCI/ful) and G2(QCI/fu2) did.The average absolute deviations (AAD) for the 125 reaction energse in the G2-l test set were reduced from 4.97 forG2(QCI) to 4.74 for G2(QCI/ful) and to 4.81kJ mol-1 for G2(QCI/fu2).The AAD was5.11 for G(fu2) compared with 5.09kJ mol-1 for G2.The reason for the larger AAD of G2(fu2) is probably due to that we did not use the better geometry of MP2(full)/6-311G(d,p) as presented in Ref.[11],and the 6-311G basis sets was somewhat unsatisfactory to describe both of the first-an secone-row atoms as had been criticized in Ref.[9].

Key words: G2 theory, G2(QCI) theory, Core electronic correlation, G2(fu2), G2(QCI/ful), G2(QCI/fu2)