Calculation of Zero-Field Splitting in NH. II. One-Center Representations of Triplet States

Abstract

The zero-field-splitting (ZFS) parameters arising from electron spin—spin dipolar interactions in the known triplet states of NH are calculated. A variety of one-center expansion (OCE) representations are utilized, including an extended basis wavefunction for the ground state. Overlaps of limited basis OCE eigenvectors with extended basis OCE eigenvectors and with two-center eigenvectors are calculated for 3Σ−NH. In addition, electron-density distributions are calculated for the various 3Σ−NH representations. It is concluded that, at least for 3Σ−NH, OCE representations in general and limited basis OCE representations in particular describe the distributions of the innermost and outermost electron shells relatively better than distributions of the remaining electrons. Electron spin—spin dipolar interaction in 3Σ−NH is found to be much larger than for 3II0NH; D=1.5951 cm−1 for 3Σ−NH using a 24 basis representation and D=0.512 cm−1 for 3II0NH using a 12 basis representation. The electronic configurations of organic nitrenes are discussed qualitatively. Directions of future ZFS calculations for nitrenes are suggested.