Premium
Computation of electronic molecular polarizabilities by a variational method at the CISD level
Author(s) -
Cartier Alain,
MartinsCosta Marilia T. C.,
Rinaldi Daniel
Publication year - 1996
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1996)60:4<883::aid-qua11>3.0.co;2-6
Subject(s) - polarizability , quadrupole , dipole , computation , gaussian , excited state , chemistry , variational method , series (stratigraphy) , atomic physics , computational chemistry , quantum mechanics , molecule , molecular physics , physics , algorithm , mathematics , biology , paleontology
The variational method proposed earlier has been generalized, using a trial function of the form: ψ = (Λ 0 + Σ s Λ s m s )ψ 0 in which m s = r 2 p +1 C m l , s standing for a triplet ( p, l, m ) and implemented into the program Hondo‐8.4. The second‐order density matrices are used to take into account the mono and bi‐excited states (DM1 and DM2 matrices, GUGA Algorithm). This allows us to compute the dipole (α), dipole‐quadrupole (A) and quadrupole (C) polarizability tensors at the CISD level. The results obtained for a series of test molecules: CO, HF, NH 3 , and methane with various gaussian basis sets are compared with experimental results (when available for A and C) and those obtained with other theoretical methods. The correlation is found to lower the values of the dipole polarizability which was generally too high when computed by the variational method at the RHF level and the values obtained here are in good agreement with the experimental ones. © 1996 John Wiley & Sons, Inc.