Impact of the DICES on the vibrational population of the neutral CO molecules remaining in their ground electronic state after the Gaussian-shaped pulse has expired

2013-08-13T00:00:00Z (GMT) by Ph V Demekhin L S Cederbaum
<p><strong>Figure 7.</strong> Impact of the DICES on the vibrational population of the neutral CO molecules remaining in their ground electronic state after the Gaussian-shaped pulse has expired. A pulse of 4 fs duration and carrier frequency of 534.2 eV (i.e. the excitation of the O(1s<sup>−1</sup>π*, <em>v<sub>r</sub></em> = 5) resonance) have been used. The populations of the <em>v</em><sub>0</sub> = 0 − 3 vibrational levels as functions of the peak intensity computed within the <em>no-DICES</em> (broken curves) and <em>DICES</em> (solid curves) models including all ionization mechanisms are shown. The sum of the populations of all vibrational 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>