NH3 AND PH3 MOLECULAR QUADRUPOLE-MOMENTS AND THE SIGNS OF MOLECULAR G-VALUES

Molecular Zeeman effect data for NH3 and PH3 was reviewed and reanalyzed to obtain molecular quadrupole moments. Since the signs of molecular g-values were not directly measured, molecular quadrupole moments were also calculated using ab initio SCF programs to remove ambiguities in the signs of g-values. For NH3, Qcc (measured) = -3.4(4) buckingham and Qcc (calculated) = -2.8 buckingham. For PH3, Qcc (measured) = -2.3(12) buckingham and Qcc (calculated) = -2.4 buckingham. These values support positive g-values for NH3 (gaa=gbb=0.568(2), gcc=0.500(2)), and for PH3 gaa=gbb=-0.325(9), and gcc=0.011(1). © 1990.