Electronic structure for the ground state of TlH from relativistic multiconfiguration SCF calculations

Abstract

The dissociation curve for the ground state of TIH was computed using a relativistic w-w coupling formalism. The relativistic effects represented by the Dirac equation were introduced using effective potentials generated from atomic Dirac-Fock wavefunctions using a generalization of the improved effecti-..e potential formulation of Christiansen, Lee and Pitzer. The multi-configuration SCF treatment used is a generalization of the two-component molecular spinor formalism of Lee, Ermler and Pitzer. Using a five configuration wavefunction we were able to obtain approximately 85% of the experimental dissociation energy. Our computations indicate that the bond is principally sigma in form, despite the large spin-orbit splitting in atomic thallium.

Relativistic calculations of dissociation energies and related properties

“…For the excited states the SO effect must be included; for AU 2 this was done on a semi-empirical basis. The molecule TiH is also of considerable interest and has been treated in both w-w coupling [21,22] and A-S coupling [23]. The latter calculations include a much more complete consideration of electron correlation and thereby yield a deeper potential well for the ground state; when this is considered, the various calculations are fully consistent.…”

Single Phase Drive Ultrasonic Motor Using LiNbO3 Rectangular Vibrator

“…To make this effect more transparent. consider the following equation, (Ji) = .f,(r")> n E z (11) where f n is a simple proportionality factor. It turns out empirically that the nonrelativistic and relativistic f,-values are nearly equal, as shown, for instance, by thef,-values for the T1-6s-state, interaction.…”

Electron Structure of Molecules with Very Heavy Atoms Using Effective Core Potentials

“…It was extended to multiconfiguration SCF (MCSCF) calculations by Christiansen and Pitzer. 13 For linear molecules this method is reasonably satisfactory sinc^ a relatively snail basis of Slater functions is adequate and the various matrix elements are calculated without particular dif ficulty. For most cases, however, a single configuration is inadequate -even more inadequate than for the nonrelativistic examples with light atoms.…”