Stark Mixing in Rydberg Systems by Ultralow Energy Collisions with Ions

Raymond Flannery, Goutham Balaraman

Dean M. Homan

A. P. Hickman, R. E. Olson, J. Pascale

D. Vrinceanu, M. Raymond Flannery

Exact classical and quantal solutions are presented for the full array of intrashell transitions $n\mathcal{l}\ensuremath{\rightarrow}n{\mathcal{l}}^{\ensuremath{'}},$ between any angular momentum states, induced by slow distant collisions with a charged particle. The collisions are adiabatic with respect to the orbital frequency of the atomic electron and the transitions are induced by the weak ion-atom dipole field generated by the ion moving along a classical path. The rich symmetry of the problem allows a unified approach and is the source of the excellent agreement, beyond the usual Ehrenfest's correspondence principle, between the classical and quantal treatments. A classical transition probability is defined. Probabilities for transition between any angular momentum states within a high Rydberg energy level are derived in exact analytic forms and are analyzed for a large number of numerical examples. The transition probabilities obtained from the three methods---quantal and classical formulations and Monte Carlo classical simulations---are directly compared to provide excellent agreement.

Robert R. Lewis, Araceli Góngora

Flannery, M. R.

First Major Highlight: Collisional Stark Mixing at ultralow energies in Rydberg Plasmas. Atoms in high (n,l) states formed in cold Rydberg plasmas decay to the ground state in a succession of radiative transitions populating intermediate excited states. Which states are populated during cascading and with what probability can be obtained from known transition probabilities. Classical models simplify the calculation considerably, revealing the "trajectory" in nt space followed during the cascade, scaling rules and other aspects hidden within the quantal approach. Conserved Quantity (quantal analogue obscure): Quantal-Classical correspondence in radiative recombination and decay is directly demonstrated. Classical transition probabilities and radiative, recombination cross-section are in excellent agreement with quantal results. Cross section for three body collisional capture is formulated for arbitrary electron-energy distributions.