Dynamic two-center resonant photoionization in slow atomic collisions

Two-center dielectronic recombination in slow atomic collisions

“…Compared to the process of collisional two-center photo ionization [16] the process considered in the present paper is more depreciated by the relative motion of the colliding centers. This motion affects quite differently the resonance conditions on which both these processes heavily rely: while these conditions are essentially not influenced by this motion in case of collisional 2CPI, it does wash out the resonant character of collisional 2CDR.…”

“…It is of interest to compare collisional 2CDR with collisional 2CPI which was studied very recently in [16]. In the 'static' situation, where the two centers constitute a bound system, both 2CDR and 2CPI show about the same effectiveness compared to the single-center radiative recombination and photo ionization, respectively.…”

“…However, since in the collisional 2CPI the source of photons is at rest with respect to resonating atoms B [16], the relative motion of centers A and B does not affect the resonant character of the first step of this process -the interaction between B and the external laser field: like in the 'static' case, atom B acts as a very efficient 'antenna' absorbing energy from the laser field and transferring it to the subsystem (e − +A). Although from the 'point of view' of the latter the transfer involves a rather broad range of energies, this does not affect its effectiveness since transitions in (e − +A) are between bound and continuum states and, thus, are not resonant.…”

“…The functions K n (x) (n = 0, 1, ..) diverge at x → 0 and decrease exponentially at x > 1 [19]. Therefore, in distant low-velocity collisions (b min 1, v 1) the most favourable conditions for 2CDR, according to (16), are realized when the energy of the incident electrons is within the small interval centered at ε p,r = ε 0 + ω B with the width ∼ δε p ∼ v/b min . Since the quantity v/b min is typically orders of magnitude larger than the natural width Γ B r we see that the collision strongly smears out the 'static' resonance con-…”

“…The strength of the two-center correlations rapidly decreases with increasing the size of the system. Nevertheless, it has recently been shown [16] that 2CPI can strongly dominate single-center photo ionization also in collisions, even though the average interatomic distance in collisions exceeds by orders of magnitude the typical size of the corresponding bound system.…”