Delayed Relaxation of Highly Excited Cationic States in Naphthalene

G. Reitsma (1) , J. Hummert (1) , J. Dura (1) , Vincent Loriot (2) , M. J. J. Vrakking (1) , Franck Lepine (2) , O. Kornilov (1)

1 MBI - Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie
2 iLM - DYNAMO - iLM - Structure et dynamique multi-échelle des édifices moléculaires

Rapid energy transfer from electronic to nuclear degrees of freedom underlies many biological processes and astrophysical observations. The efficiency of this energy transfer depends strongly on the complex interplay between electronic and nuclear motions. In this study, we report two-color pump–probe experiments that probe the relaxation dynamics of highly excited cationic states of naphthalene, a prototypical polycyclic aromatic hydrocarbon molecule, which are produced using wavelength-selected, ultrashort extreme ultraviolet pulses. Surprisingly, the relaxation lifetimes increase with the cationic excitation energy. We postulate that the observed effect is the result of a population trapping that leads to delayed relaxation.

Keywords: Aromatic compounds; Ionization; Hydrocarbons; Energy; Excited states

Domains: Chemical Sciences; Physics [physics]; Engineering Sciences [physics]

G. Reitsma, J. Hummert, J. Dura, Vincent Loriot, M. J. J. Vrakking, et al.. Delayed Relaxation of Highly Excited Cationic States in Naphthalene. Journal of Physical Chemistry A, 2019, 123 (14), pp.3068-3073. ⟨10.1021/acs.jpca.8b10444⟩. ⟨hal-02285862⟩