Comparative study of Green's function matrix elements and charge transfers obtained from different partitioning schemes of molecular charge in hydrogen-bonded complexes

Journal of the Brazilian Chemical Society

Gama, A. Arnóbio S. da¹  Parnaíba-da Silva, Antenor J.¹  Silva, João Bosco P. da¹  Universidade Federal de Pernambuco¹  Ramos, Mozart N.¹ 

关键词: hydrogen bond;    ab initio calculations;    charge transfer;    Green's function;    atomic charge partitioning;   

DOI  :  10.1590/S0103-50532006000200004

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

RHF and MP2 ab initio molecular orbital calculations using the 4-31G**, 6-311G** and cc-pVTZ basis sets have revealed that the Green's function matrix element (GD,A) values show a good correlation with the amount of intermolecular transferred charges obtained from different charge partitioning schemes for the CNH…CNH, NCH…CNH, CNH…NCH and NCH…NCH hydrogen bonded complexes. This is evident specially when the hydrogen bond distance is progressively increased from the equilibrium position until 4.5 Å. However, GD,A values show a better linear correlation with DQ values using corrected Mülliken charges, which are obtained from the charge-charge flux-overlap (CCFO) model for infrared intensities. In this case, both GD,A and DQcorr form two practically superposed exponential curves. On the other hand, GD,A values show a smaller agreement with DQ values obtained from atomic charges derived from natural bonding orbitals. This is clearly verified when considering the first order exponential decay rate of GD,A versus DQ obtained from different charge partitioning schemes.

【 授权许可】

Unknown