6533b7d6fe1ef96bd1265a0f
RESEARCH PRODUCT
CCSDT calculations of molecular equilibrium geometries
Trygve HelgakerAsger HalkierJürgen GaussPoul Jørgensensubject
Bond lengthBasis (linear algebra)Computational chemistryChemistryGeneral Physics and AstronomyPhysical and Theoretical ChemistryMolecular physicsBasis setdescription
Abstract CCSDT equilibrium geometries of CO, CH2, F2, HF, H2O and N2 have been calculated using the correlation-consistent cc-pVXZ basis sets. Similar calculations have been performed for SCF, CCSD and CCSD(T). In general, bond lengths decrease when improving the basis set and increase when improving the N-electron treatment. CCSD(T) provides an excellent approximation to CCSDT for bond lengths as the largest difference between CCSDT and CCSD(T) is 0.06 pm. At the CCSDT/cc-pVQZ level, basis set deficiencies, neglect of higher-order excitations, and incomplete treatment of core-correlation all give rise to errors of a few tenths of a pm, but to a large extent, these errors cancel. The CCSDT/cc-pVQZ bond lengths deviate on average only by 0.11 pm from experiment.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1997-08-01 | Chemical Physics Letters |