High-harmonic transient grating spectroscopy of NO 2 electronic relaxation

H. Ruf (1) , C. Handschin (1) , A. Ferré (1) , Nicolas Thiré (2, 3) , J. Bertrand (4, 5) , L. Bonnet (6) , Raluca Cireasa (2, 3) , E. Constant (1) , P. Corkum (4, 5) , D. Descamps (1) , B. Fabre (1) , P. Larregaray (6) , E. Mével (1) , S. Petit (1) , B. Pons (1) , David Staedter (2, 3) , H. Wörner (4, 5) , D. Villeneuve (4, 5) , Y. Mairesse (1) , P. Halvick (6) , V. Blanchet (1, 2, 3)

1 CELIA - Centre d'Etudes Lasers Intenses et Applications
2 LCAR - Laboratoire Collisions Agrégats Réactivité
3 Femto (LCAR)
4 Joint Attosecond Science Laboratory
5 University of Ottawa [Ottawa]
6 ISM - Institut des Sciences Moléculaires

We study theoretically and experimentally the electronic relaxation of NO(2) molecules excited by absorption of one ∼400 nm pump photon. Semiclassical simulations based on trajectory surface hopping calculations are performed. They predict fast oscillations of the electronic character around the intersection of the ground and first excited diabatic states. An experiment based on high-order harmonic transient grating spectroscopy reveals dynamics occurring on the same time scale. A systematic study of the detected transient is conducted to investigate the possible influence of the pump intensity, pump wavelength, and rotational temperature of the molecules. The quantitative agreement between measured and predicted dynamics shows that, in NO(2), high harmonic transient grating spectroscopy encodes vibrational dynamics underlying the electronic relaxation.

Domaines: Chimie-Physique [physics.chem-ph]; Agrégats Moléculaires et Atomiques [physics.atm-clus]

H. Ruf, C. Handschin, A. Ferré, Nicolas Thiré, J. Bertrand, et al.. High-harmonic transient grating spectroscopy of NO 2 electronic relaxation. Journal of Chemical Physics, 2012, 137 (22), pp.224303. ⟨10.1063/1.4768810⟩. ⟨hal-03491672⟩