No abstract

Quantum and semiclassical description of a triply degenerate anharmonic oscillatorThe propagation of an initially highly excited localized wave packet in an anharmonic oscillator potenti~ is stu~ied within th~ frozen Gaussian approximation. Comparison is made to quantum mec.h~lcal basIS set ~alc~lat1ons. The frozen Gaussian approximation involves the expansion of the ID1t1al wave function 10 terms of an overcomplete Gaussian basis set. The wave function evolution is ~v.aluated by allowing eac~ Gaussian to travel along a classical trajectory with its shape held n81d. A Monte Carlo algonthm is employed in the selection of the initial Gaussian basis functions. The frozen Gaussian results are very good for times on the order of a few vibrational periods of the oscillator and remain qualitatively correct for the entire length of the calculations which is 12 vibrational periods. The dependence of the calculations on the width of the Gaussian basis functions is investigated and the effect of a simplifying approximation for the prefactor of the Gaussians is tested.

No abstract