An Ab Initio calculation of the spin dipole‐dipole parameters for methylene

The electron spin dipole‐dipole interaction in CH 2 has been calculated as a function of bond angle with configuration‐interaction wave functions built from contracted gaussianlobe basis functions. The values D = 0.781 cm −1 and E = 0.050 cm −1 were obtained for the spin dipole‐dipole contribution to these parameters for the best CI wave function at the equilibrium geometry. The angular dependence of D shows that the assumption of perfect orbital following is not valid. Based on previous estimates of the spin‐orbit contribution to D , the total D is estimated to be 0.9 ± 0.1 cm −1 which is higher than the current experimental value 0.76 ± 0.02 cm −1 .