A. Norman Jette

Fine structure in Rydberg states of the H2 molecule

Abstract The electron spin—nuclear rotation interaction is considered for the n p 3 Π u Rydberg series of the H 2 molecule for which much experimental data is available. Earlier formulations of this interaction are reconciled and consistent formulae for both the heteronuclear and homonuclear case are presented. Theoretical calculations of various contributions are given and compared to experimental results. Excellent agreement between calculated and experimental values is obtained for the n p Rydberg series of H 2 including H 2 + .

Spin‐other‐orbit and spin‐spin interactions in the metastable, c3Πu(1s,2p) state of H2

An ab initio calculation of the spin‐other‐orbit and spin‐spin interactions in the c 3Πu(1s,2p) state of molecular hydrogen has been made. This calculation utilized the wavefunction obtained with the optimal double configuration model by Zemke, Lykos, and Wahl. The coupling constants are in good agreement with those calculated by Lombardi using the 45–50 configuration elliptic coordinate wavefunction of Rothenberg and Davidson.

Fine-structure of the metastable, c3 Πu (1s, 2p), state of molecular hydrogen☆

Abstract The energy splittings of a single rotational level of metastable parahydrogen have been attributed to spin-orbit, spin-other-orbit and spin-spin interactions. However, there is a discrepancy between this theory and the experimental results in the prediction of the spin-orbit coupling constant. Experiment gives different values for this constant in ortho- and para-hydrogen differing by 2 1 2 %. It is shown that when one properly takes into account the spin-rotational interaction between the electrons and nuclear frame work this discrepancy is resolved.

Valence bond study of hyperfine interactions and structure of the noble gas monohalides

A semiempirical valence bond (VB) wavefunction that includes correlation between electrons of opposite spin is used to calculate hyperfine structure constants (hfc) of the noble gas monohalide molecules (NX). This wavefunction has the form ψ =N (2Σ)[χAΦ (N⋅⋅⋅X)+(1−χ2)1/2 AΦ (N+⋅⋅⋅X−)] where N and X denote the noble gas and halogen, respectively, and A is the antisymmetrization operator. This antisymmetrization and the effects of interatomic electron correlation on open shell states are the major contributors to the isotropic hfc. These correlation effects are treated by perturbation theory calculations of the van der Waals polarization of X by N in the VB structure Φ (N⋅⋅⋅X) and the Coulomb polarization of N+ by X− in Φ (N+⋅⋅⋅X−). It is also important to consider both valence and inner shell s electrons, and to include intra‐atomic electron correlation. The latter is treated by using neutral atom orbitals for N and X in Φ (N⋅⋅⋅X) and cation and anion orbitals for N+ and X−, respectively, in Φ (N+⋅⋅⋅X−). C...

Coupling constants of the fine and hyperfine interaction in the c 3Πu metastable state of H2

Ab initio calculations of the fine and hyperfine coupling constants in the metastable state of molecular hydrogen are extended to internuclear distances of 1.90 and 2.00 a.u. From these results averaged coupling constants for the N=1 rotational state of orthohydrogen and the N=2 state of parahydrogen are obtained over the zeroth vibrational level.

Erratum: The ab initio calculation of the spin–rotational coupling in the metastable c Πu (1s,2p) state of molecular hydrogen

An ab initio calculation of the spin–rotational coupling C for the c 3Πu(1s,2p) state of H2 gives a result within 7% of the experimental constant. The primary contribution to the spin–rotational coupling is found to be the 1sσg one electron molecular orbital. (AIP)

Semiempirical model of the exchange polarization mechanism of transferred hyperfine interactions in ionic radicals

This paper presents a semiempirical method for calculating metal hyperfine interaction constants in ionic radicals whose zero‐order wave function places the unpaired electron completely on the anion with zero overlap between it and the relevant cation orbitals. The mechanistic basis of the calculation is spin polarization of closed‐shell anion orbitals by their exchange interaction with the unpaired electron, followed by partial transfer of the resulting unpaired electron density in these anion orbitals to the cation orbitals via overlap. The exchange polarization is described by a perturbation theory expansion in anion excited states, which expansion is summed by introducing semiempirical average excitation energies. The contribution of direct exchange polarization of the cation orbitals to the cation hyperfine interactions is found to be negligible, due primarily to the very large excitation energies of the cation core orbitals. Calculated results are compared with experiment for the ionic radicals Na(C=CH2) and NaO2.

Semiempirical valence bond model of hyperfine interactions and bonding in RbO and CsO

The alkali hyperfine structure (hfs) splittings in the 2Σ radicals RbO and CsO are analyzed using a semiempirical valence bond (VB) wave function similar to that used previously for the noble gas monohalides. For the alkali monoxides this wave function is ψ=N(2Σ)[χAΦ(M+ ⋅ ⋅ ⋅ O−) +(1−χ2)1/2AΦ(M++ ⋅ ⋅ ⋅ O=)], where M and O denote the alkali and oxygen, respectively, and A is the antisymmetrization operator. This antisymmetrization and the effects of interatomic electron correlation in the Φ(M++ ⋅ ⋅ ⋅ O=) VB structure are the principal contributors to the hfs. At the bond distances RRbO=4.30 and RCsO=4.67a0 the parameters χ=0.9996 and 0.9967 for RbO and CsO, respectively, give good agreement between theory and experiment for both the isotropic and anisotropic hfs. The admixture of the doubly ionized Φ(M++ ⋅ ⋅ ⋅ O=) VB structure, which produces covalent bonding involving the alkali cation core orbitals and the oxygen anion valence orbitals, is small as expected from the high energy of this structure.

Valence bond study of hyperfine interactions and structure of Kr2F

Abstract A semi-empirical valence bond method for calculating isotropic and anisotropic hyperfine interaction constants in diatomic halogen anions and noble gas monohalides has been extended to the linear triatomic KrFKr. Comparison with the experimental values yields estimates for the KrF bond distance and the electron charge distribution in Kr 2 F.