Eugene J. McGuire

Three‐photon resonance ionization of H2

Calculations are performed for the ionization of para‐H2 by absorption of three 6.6 eV photons. Two photons are absorbed to excite H2 to the E, F 1Σ+g state, and a third photon is absorbed to ionize this state. The two‐photon Rabi rate and one‐photon ionization rate are linear in the laser intensity (I) and are thus competitive. This competition produces a strong dependence of the three‐photon ionization rate on the vibrational‐rotational levels of the bound–bound electronic transition and on the electron ejection angle. For example, for I = 1 GW cm−2 the strong (maximum ionization rate 6×108 s−1/molecule) vJ = 00→v′J′ = 30 transition is 70% saturated at 0° and 100% saturated at 90° ejection angle relative to the linear polarization direction of the photon. The weak (maximum ionization rate 2×1 07 s−1/molecule) vJ = 00→v′J′ = 32 transition is 0.3% saturated at 0° and 80% saturated at 90° ejection angle. These calculations suggest use of multiphoton ionization data to study one‐photon excited‐state angular...

Multiplet Auger transition rate for partially filled shells

A previous derivation of the generalized Auger transition for inner-shell multiplets is shown to be incorrect. The previous derivation was based on deducing a coupling scheme from 6-j symbols in the transition-rate expression, then transforming the coupling coefficients. It was expected that the transformed transition rate would be correct up to a phase factor. It is shown here that this expectation is incorrect (i.e., incorrect irrespective of phase factor). Correct expressions are obtained by direct manipulation of 6-j and 9-j symbols. It is shown that the correct expression can be found using the coupling tansformation provided a modified matrix element expression is used. (auth)