Impact of the DICES on the rotational population of the neutral CO molecules remaining in their ground electronic state after the Gaussian-shaped pulse of 4 fs duration and carrier frequency of 534.2 eV have expired

2013-08-13T00:00:00Z (GMT) by Ph V Demekhin L S Cederbaum
<p><strong>Figure 8.</strong> Impact of the DICES on the rotational population of the neutral CO molecules remaining in their ground electronic state after the Gaussian-shaped pulse of 4 fs duration and carrier frequency of 534.2 eV have expired. Before the pulse arrived, the target CO molecules were isotropically oriented, i.e. in the ground rotational state <em>J</em><sub>0</sub> = 0. The populations of the <em>J</em><sub>0</sub> rotational levels for the <em>v</em><sub>0</sub> = 0 − 2 vibrational levels as a function of peak intensity computed exactly, i.e. <em>DICES</em> model and <em>Total</em> (no approximations) are shown. For each vibrational level <em>v</em><sub>0</sub>, the sum of the populations of all rotational levels is normalized to 100% at each peak intensity.</p> <p><strong>Abstract</strong></p> <p>The dynamics of the resonant Auger (RA) decay of the core-excited CO*(1s<sup>−1</sup>π*) molecule in intense x-ray laser pulses is studied theoretically. The present approach includes the impact of the analogue of conical intersections of the complex potential energy surfaces of the ground and 'dressed' resonant states induced by intense x-ray pulses. It also takes into account the decay of the resonance and the direct photoionization of the ground state, both populating the same final ionic states coherently, as well as the direct photoionization of the resonance state itself. The individual impacts of these physical processes on the total ion yield, the CO<sup>+</sup>(<em>A</em> <sup>2</sup>Π) electron spectrum and the ro-vibrational distributions of the neutral molecules remaining in the ground electronic state after the laser pulse has expired are analysed and compared to those reported previously for the C*O resonance. It is also demonstrated that the RA effect of molecules by strong laser pulses of resonant carrier frequency is an efficient process to produce <em>two-site double-core-hole–one-particle</em> states of CO*.</p>