6533b823fe1ef96bd127e025

RESEARCH PRODUCT

Analytic UHF-CCSD(T) second derivatives: implementation and application to the calculation of the vibration-rotation interaction constants of NCO and NCS

John F. StantonJürgen GaussPéter G. Szalay

subject

VibrationRenner–Teller effectChemistryExcited stateHarmonicPhysics::Chemical PhysicsPhysical and Theoretical ChemistryAtomic physicsGround stateRotation (mathematics)ExcitationSecond derivative

description

An implementation of analytic open-shell UHF-CCSD(T) second derivatives is presented. To demonstrate applicability and test the accuracy of the UHF-CCSD(T) approach for the determination of spectroscopical parameters, vibration-rotation interaction constants were calculated for the ground (12Π) and first electronically excited (12Σ) states of the NCO and NCS radicals. In addition, harmonic vibrational frequencies for both states, the Renner-Teller parameter for the ground state, as well as the 12Π→12Σ excitation energy are reported. While the computed values are in good agreement with reliable experimental information for NCO, most of the data presented for NCS are predictions of quantities not well known from experiment.

yearjournalcountryeditionlanguage
1998-11-30Theoretical Chemistry Accounts: Theory, Computation, and Modeling (Theoretica Chimica Acta)
https://doi.org/10.1007/s002140050360