6533b826fe1ef96bd1284f31
RESEARCH PRODUCT
A MRCI PS and CASSCF study of the ground state MgO dissociation energy
I. Nebot GilI. García CuestaA. Sánchez De Merássubject
ChemistryComputational chemistryAb initio quantum chemistry methodsExcited stateAnharmonicityGeneral Physics and AstronomyRotational spectroscopyPhysical and Theoretical ChemistryAtomic physicsWave functionGround stateDiatomic moleculeBond-dissociation energydescription
Abstract Ab initio calculations at CASSCF and MRCI PS levels are used to determine the dissociation energy for the X 1 Σ + state of MgO, which adiabatically dissociates to the ground state 1 S g of magnesium and to the excited 1 D g state of oxygen, as well as other spectroscopic parameters. Emphasis is placed upon the problem of properly selecting an adequate active space in CASSCF calculations and upon the improvements obtained in MRCI by selecting perturbatively the most important contributions to the total wavefunction and evaluating the remaining ones only by perturbational method. Through a procedure based on stabilizing the computed dissociation energy, values of 3.87 eV (MRCI PS) and 4.20 eV (CASSCF) are obtained. These values compare with the experimental value of 3.76±0.13 eV.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1991-11-01 | Chemical Physics Letters |