Dipole hyperpolarizability surfaces of ammonia

摘要

Fullhyphen;dimensional first dipole hyperpolarizability surfaces of NH3are determined by means of multiconfigurational quadratic response theory. On the basis of the twohyphen;dimensional, symmetric stretching vs inversion, hyperpolarizability functions, and approximate vibrational wave functions, effective inversional hyperpolarizability moments are evaluated for theD3hammonia isotopomers. The calculations have revealed their strong vibrational and frequency dependence. A fairly close reproduction of the first hyperpolarizability ESHG constant bgr; (632.8 nm) by theory indicates that the major correction to the onehyphen;particle hyperpolarizability is obtained by variational wave functions including a comparatively small set of active orbitals. We find that a meaningful comparison with experimental results can only be obtained by an appropriate evaluation of both the vibrational and the correlated dispersion dependencies.