6533b854fe1ef96bd12adddb

RESEARCH PRODUCT

Anharmonic force fields from analytic CCSD(T) second derivatives: HOF and F2O

Walter ThielJohn F. StantonJürgen GaussJürgen Breidung

subject

Coupled clusterHydrogen compoundsChemistryQuartic functionQuantum mechanicsAnharmonicityPhysics::Atomic and Molecular ClustersFinite difference methodFinite differenceGeneral Physics and AstronomyPhysical and Theoretical ChemistryPerturbation theorySecond derivative

description

The recent implementation of analytic second derivatives for CCSD(T) (coupled cluster theory with single and double excitations augmented by a perturbational treatment of connected triple excitations) has been combined with a numerical finite difference procedure to calculate cubic and semidiagonal quartic force fields. Computational details of this approach are outlined. Applications are reported for HOF and F2O. The CCSD(T) results are in excellent agreement with experiment and represent a substantial improvement over the results obtained from MP2 (Mo/ller–Plesset second-order perturbation theory).

https://doi.org/10.1063/1.478258