The intrapair and interpair correlation energies of F -, HF and H 2F +systems are calculated and analyzed using MP2 OPT2 method of MELD program with cc PV5Z * basis set. From the analysis of pair correlation ene...The intrapair and interpair correlation energies of F -, HF and H 2F +systems are calculated and analyzed using MP2 OPT2 method of MELD program with cc PV5Z * basis set. From the analysis of pair correlation energies of these isoelectronic systems, it is found that the 1s F 2 pair correlation energy is transferable in these three isoelectronic systems. According to the definition of pair correlation contribution of one electron pair to a system, the pair correlation contribution values of these three systems are calculated. The correlation contribution values of inner electron pairs and H—F bonding electron pair in HF molecule with those in H 2F +system are compared. The results indicate that the bonding effect of a molecule is one of the important factors to influence electron correlation energy of the system. The comparison of correlation energy contributions including triple and quadruple excitations with those only including singles and doubles calculated with 6 311++G(d) basis set shows that the higher excitation correlation energy contribution gives more than 2% of the total correlation energy for these systems.展开更多
The calculation results of electron correlation energies of KF and （KF）2 were reported. The transferability of 1s^2 K , 1s^2 F and the inner core correlation effects of K and F in both K, K^＋, KF and F, F^-, KF sys...The calculation results of electron correlation energies of KF and （KF）2 were reported. The transferability of 1s^2 K , 1s^2 F and the inner core correlation effects of K and F in both K, K^＋, KF and F, F^-, KF systems were investigated respectively. The correlation energy contributions of K and F component to KF system were calculated. By applying the simple estimation scheme to the calculation of the correlation energy of the strong ionic compound KF and （KF）2, it was shown that such a powerful scheme could not only reach the chemical accuracy but also need little computational work.展开更多
Based on the calculation results of pair correlation energy contributions of the various electron pairs in Na2 and H2NNH2 systems and the application of the scaling ionic partition scheme for symmetrical A2 type syste...Based on the calculation results of pair correlation energy contributions of the various electron pairs in Na2 and H2NNH2 systems and the application of the scaling ionic partition scheme for symmetrical A2 type systems, the to-tal correlation energies of Na2 and H2NNH2 have been reproduced by using this simple scheme. The two results show that the absolute deviations are within an acceptable range of error, however, in this way, more than 90% of computational work can be saved. The most attractive result in present paper is that, in these two molecules the co-efficients c1 and c2 in the estimation equation can be obtained by the proportion of correlation energy of A- to that of A+ singlet system. Therefore, it is believed that the proposed ionic partition scheme for symmetrical A2 mole-cules would be very useful to estimate the correlation energies of large symmetrical molecules.展开更多
文摘The intrapair and interpair correlation energies of F -, HF and H 2F +systems are calculated and analyzed using MP2 OPT2 method of MELD program with cc PV5Z * basis set. From the analysis of pair correlation energies of these isoelectronic systems, it is found that the 1s F 2 pair correlation energy is transferable in these three isoelectronic systems. According to the definition of pair correlation contribution of one electron pair to a system, the pair correlation contribution values of these three systems are calculated. The correlation contribution values of inner electron pairs and H—F bonding electron pair in HF molecule with those in H 2F +system are compared. The results indicate that the bonding effect of a molecule is one of the important factors to influence electron correlation energy of the system. The comparison of correlation energy contributions including triple and quadruple excitations with those only including singles and doubles calculated with 6 311++G(d) basis set shows that the higher excitation correlation energy contribution gives more than 2% of the total correlation energy for these systems.
基金Project supported by the National Natural Science Foundation of China （No. 20173027） and the Natural Science Foundation of Shandong Province （No. 2003ZX04）.
文摘The calculation results of electron correlation energies of KF and （KF）2 were reported. The transferability of 1s^2 K , 1s^2 F and the inner core correlation effects of K and F in both K, K^＋, KF and F, F^-, KF systems were investigated respectively. The correlation energy contributions of K and F component to KF system were calculated. By applying the simple estimation scheme to the calculation of the correlation energy of the strong ionic compound KF and （KF）2, it was shown that such a powerful scheme could not only reach the chemical accuracy but also need little computational work.
文摘Based on the calculation results of pair correlation energy contributions of the various electron pairs in Na2 and H2NNH2 systems and the application of the scaling ionic partition scheme for symmetrical A2 type systems, the to-tal correlation energies of Na2 and H2NNH2 have been reproduced by using this simple scheme. The two results show that the absolute deviations are within an acceptable range of error, however, in this way, more than 90% of computational work can be saved. The most attractive result in present paper is that, in these two molecules the co-efficients c1 and c2 in the estimation equation can be obtained by the proportion of correlation energy of A- to that of A+ singlet system. Therefore, it is believed that the proposed ionic partition scheme for symmetrical A2 mole-cules would be very useful to estimate the correlation energies of large symmetrical molecules.
