Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9575413 | Chemical Physics | 2005 | 7 Pages |
Abstract
Spin-orbit effects on the spectroscopic constants (bond lengths, dissociation energies and harmonic vibrational frequencies) for HX, X2 (X = Cl, Br and I) and IZ (Z = F, Cl and Br) molecules have been studied using shape-consistent relativistic effective core potentials (RECPs) with effective one-electron spin-orbit operator at HF, MP2, CCSD and CCSD(T) levels. Basis sets of pVTZ quality have been derived for Cl, Br and I for the present work. The spectroscopic constants calculated by the two-component RECP method are in good agreement with those from all-electron Dirac-Coulomb calculations with the basis sets of the similar quality at all levels of theory considered, suggesting that RECP methods mimic all-electron Dirac-Coulomb methods calculations rather well for molecules. Spin-orbit effects elongate the bond lengths, while reduce the dissociation energies and harmonic vibrational frequencies. From the spin-orbit effects on the spectroscopic constants, especially on dissociation energies of IF, ICl, IBr and I2, it is confirmed that the magnitude of spin-orbit effects increases in the F < Cl < Br < I order. Spin-orbit effects constitute a significant portion of relativistic effects for the studied molecules. For the dissociation energies of the studied molecules, the spin-orbit effects and electron correlation effects are slightly non-additive, implying the need of spin-orbit calculations at the correlated level for the high accuracy.
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Hyo Sug Lee, Woo Kyung Cho, Yoon Jeong Choi, Yoon Sup Lee,