Singly Resonant Multiphoton Processes Involving Autoionizing States in the Be-like CIII Ion

In this paper, we investigate the applicability of different theories on intensity-dependent ionization rate for C2+ atomic targets at laser wavelengths (frequency) and linear polarization. We use analytical formulas draw conclusions, from numerical comparison with results ab initio ‘two-state model’ R-matrix Floquet calculation, their correct predictions rate. The single-photon has been studied in vicinity 1s2 (2Po)2pns (1Po), n = 5–12 autoionizing resonances non-perturbative intensity. obtained Perelomov–Popov–Terent’ev Ammosov–Delone–Krainov models are compared a region away resonance where two-state model description is not as good. To quantify deviation between theoretical models, analyze ratio data sets functions Keldysh parameter. conclude that Perelemov–Popov–Terent’ev closest to calculation.