Nonlinear selective photoprocesses in atoms and molecules

Donald W. Goodwin

D.C. Hanna, Michael A. Yuratich, D. Cotter

А. В. Аристов, Victor S. Shevandin

Valery Alexandrovich Astapenko

Vadim A. Markel, M. I. Shtokman

We consider sationary fluctuations due to nonlinear excitation in a bichromophore, that is, in a molecule consisting of two chromophoric groups. We describe correlated fluctuations of the level populations and of the flux of flourescent photons emitted by a bichromophore. The population fluctuations are observable in experiments involving quasielastic particle scattering or Raman scattering of probe radiation. Experiments of this kind can yield information about the rate of nonradiative energy transfer. The photon correlation is characterized by antibunching and sub-Poissonian statistics and can yield information about collective excitation and nonlinear quenching.

Valery Alexandrovich Astapenko, Sergey V. Sakhno

The development of methods of generation of ultrashort pulses (USP) of femto- and attosecond duration ranges with controlled parameters necessitates the theoretical study of features of their interaction with a matter [1]. Among such features that do not exist in case of “long” pulses should first of all be the nonlinear dependence of the photoprocess probability W on the USP duration (τ) [2] as well as the dependence on the carrier phase with respect to the pulse envelope (φ) [3-4]. It should be noted that if the dependence of the probability W on the phase φ manifests itself either only for very short pulses, when ωτ < 1 (ω is carrier frequency of the pulse), or in case of a nonlinear photoprocess [3], the function W(τ) can differ from a linear function in the limit ωτ> 1 too for fields of moderate strength, when the perturbation theory is applicable [2].