Imaging of rotational wave-function in photodissociation of rovibrationally excited HCl molecules

0471293 - ÚFCH JH 2018 RIV US eng J - Článek v odborném periodiku
Grygoryeva, Kateřina - Rakovský, Jozef - Votava, Ondřej - Fárník, Michal
Imaging of rotational wave-function in photodissociation of rovibrationally excited HCl molecules.
Journal of Chemical Physics. Roč. 147, č. 1 (2017), č. článku 013901. ISSN 0021-9606. E-ISSN 1089-7690
Grant CEP: GA ČR GA14-08937S; GA ČR GA13-11635S
Institucionální podpora: RVO:61388955
Klíčová slova: Angular distribution * Chemical reactions * Photodissociation
Obor OECD: Physical chemistry
Impakt faktor: 2.843, rok: 2017

We demonstrate a visualization of quantum mechanical phenomena with the velocity map imaging (VMI) technique, combining vibrationally mediated photodissociation (VMP) of a simple diatomic HCl with the VMI of its H-photofragments. Free HCl molecules were excited by a pump infrared (IR) laser pulse to particular rotational J levels of the nu = 2 vibrational state, and subsequently a probe ultraviolet laser photodissociated the molecule at a fixed wavelength of 243.07 nm where also the H-fragments were ionized. The molecule was aligned by the IR excitation with respect to the IR laser polarization, and this alignment was reflected in the angular distribution of the H-photofragments. In particular, the highest degree of molecular alignment was achieved for the J = 1 0 transition, which exclusively led to the population of a single rotational state with M = 0. The obtained images were analyzed for further details of the VMP dynamics, and different J states were studied as well. Additionally, we investigated the dynamic evolution of the excited states by changing the pump-probe laser pulse delay. The corresponding images reflected dephasing due to a coupling between the molecular angular momentum and nuclear spin. Our measurements confirmed previous observation using the time-of-flight technique by Sofikitis et al. [J. Chem. Phys. 127, 144307 (2007)]. We observed a partial recovery of the originally excited state after 60 ns in agreement with the previous observation. Published by AIP Publishing.
Trvalý link: http://hdl.handle.net/11104/0268682