Excitation of pseudorotational vibronic motion through femtosecond pump-probe spectroscopy:: A 2D computational study

The real-time excitation and detection of radial and pseudorotational vibronic motions of Jahn-Teller and pseudo-Jahn-Teller coupled systems is studied theoretically. A previously developed 2D description of ground and excited electronic states of the sodium trimer, Ng, is employed as a realistic model system. Within this scheme the detection of vibronic motions proceeds by measuring the ion signal, possibly resolved for the kinetic energy of the ejected photoelectrons. It is demonstrated how by changing Various pulse parameters, such as pulse length, strength, or carrier frequency, radial or pseudorotational motions in the ground or excited electronic states are selectively excited. The particularly interesting-and difficult-case of exciting the pseudorotational motion in the ground state manifold can be realized by using three different pulses.