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

Antenor J. Parnaíba-da Silva¹  João Bosco P. Da Silva¹  A. Arnóbio S. Da Gama¹  Mozart N. Ramos¹ 

[1] ,Universidade Federal de Pernambuco Departamento de Química Fundamental

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

DOI  :  10.1590/S0103-50532006000200004

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 (G D,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, G D,A values show a better linear correlation with deltaQ values using corrected Mülliken charges, which are obtained from the charge-charge flux-overlap (CCFO) model for infrared intensities. In this case, both G D,A and deltaQcorr form two practically superposed exponential curves. On the other hand, G D,A values show a smaller agreement with deltaQ values obtained from atomic charges derived from natural bonding orbitals. This is clearly verified when considering the first order exponential decay rate of G D,A versus deltaQ obtained from different charge partitioning schemes.

【 授权许可】

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