The interference phenomena at negative ion photodecay in a bichromatic field

Abstract

The interference phenomena which can take place at the negative ion photodecay in a bichromatic electromagnetic (EM) field of linear and circular polarization consisting of coherent superposition of commensurable th and th harmonics of the same fundamental field are studied within the confines of the theory of perturbation on EM interaction and a zero-range potential model for the negative ion. The case of both odd and and that of odd and even (or vice versa) have been considered. It has been shown that, in the first case, the angular distribution of the emitted photoelectrons is always completely polar symmetric (in respect of the replacement , here p is the photoelectron momentum) and that the total photodecay probability is a periodic function of phase shift between harmonics. However, in the second case of odd and even , the angular distribution has polar asymmetry the degree of which depends on the values of and ratio of the electric vector strengths of the harmonics. Unlike the first case however, the total photodecay probability does not depend on phase shift at all. Moreover, the importance of taking into account the intermediate intercontinuum EM transitions (accompanied with the photoelectron momentum and energy change) has been shown too.