ELECTRON-SPIN G-FACTORS OF H-2(-) - AN AB-INITIO STUDY

In ESR studies of gamma-irradiated solid pH(2), a peak is observed hav ing a large positive g-shift, which, according to Symons (Chem. Phys. Lett. 247 (1995) 607), may be attributable to H-2(-) trapped in the H- 2 matrix. To test this hypothesis, theoretical Delta g-values for the resonant 2 Sigma(u)(+)(1 sigma(g)(2) 1 sigma(u)) state of isolated H-2 (-) as computed at the ROHF level are reported. The calculated g-shift s are small and negative (Delta g(parallel to) = -27 ppm, Delta g(perp endicular to) = -23 ppm), remaining close to a Delta g-value of -35 pp m for the H(S-2) atom. The findings do not support the assertion that Delta g(H-2(-)) could be as high as + 1000 ppm.