Dissociative Recombination of Slow Electrons and Molecular Oxygen Ions in a Strong Laser Field

Abstract

The reaction of low-temperature dissociative recombination $$\begin{array}{*{20}{c}} {{e^ - }(l\Lambda ) + O_2^ + {(^2}{\Pi _g},v = 0)\xrightarrow{{k{\omega _f}}}} \\ {\left[ {O_2^{ * * }({n_k}p{\pi _u}({B^3}\sum _u^ - )) \Leftrightarrow O_2^*({B^3}\sum _u^ - )} \right] \to O({}^3P) + O({}^1D)} \end{array}$$ (1) was investigated. It takes place due to direct and resonance radiationless transitions (k=0) into the Schumann-Runge continuum (B 3∑ u − ) and due to free-bounded radiation transitions (k=1) into predissociative Rydberg n 1 pπu(B 3∑ u − ) states by the action of monochromatic laser field with frequency ω f in the visible region. Index k denotes the change in the number of photons in the system, n k is the principal quantum number at the prescribed k value, v is the vibrational quantum number, and l and Λ are the electron orbital momentum and its projection on the molecular axis, respectively. The electron energy is assumed to be small and lies in the interval 0 < E e < ω , where ω is the ion vibrational frequency. Under the condition ( ħ= m e = e = 1 ) $$pf\omega _f^{ - 2} \ll 1, p = \sqrt {2{E_e},}$$ (2) where p is the impulse of incident electron and f is the amplitude of electromagnetic field intensity. The electron oscillation amplitude is many times smaller than its wavelength. The external field in that case has no influence on the electron motion, i.e. the electron has the definite energy, E e . The field mostly affects the states of the intermediate complex XY** if it does not lead to dipole allowed transitions in the isolated ion XY + . In this case the electron motion is multichannel. The second restriction on the external field strength is $$ fD < < 1, $$ (3) where D is ihe dipole moment of the transition.