Potential energy surface inversion splitting

Inversion Potential Function. In a large-scale study, 93 points on the potential energy surface of the ground electronic state X A of PH3 were determined by ab initio SCF + second-order Moller-Plesset perturbation calculations (MP2). A polynomial potential function (earlier applied to NH3 [30]) was fitted to these points [13]. The calculated vibration-rotation energies are in reasonable agreement with the experiment [13]. For calculated inversion splittings, see above. 

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