### Session L26: Focus Session: Non-adiabatic Molecular Dynamics and Control at Conical Intersections III

2:30 PM–5:18 PM, Tuesday, March 6, 2007

Abstract ID: BAPS.2007.MAR.L26.4

### Abstract: L26.00004 : Probing NO$_{2}$ close to the $\tilde {A}{ }^2B_2 /\tilde {X}{ }^2A_1$ conical intersection by time-resolved imaging spectroscopy

3:54 PM–4:06 PM

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#### Authors:

Benjamin Whitaker
(University of Leeds, UK)

Nick Form
(University of Leeds, UK)

Valerie Blanchet
(Universite Paul Sabatier, Toulouse)

Beatrice Chatel
(Universite Paul Sabatier)

Bertrand Girard
(Universite Paul Sabatier)

Time-resolved imaging spectroscopy (TRIS) is emerging as a versatile technique with which to study the non-adiabatic coupling of vibrational and electronic degrees of freedom in molecules. The electronic predissociation of NO$_{2}$ in the near UV proceeds by internal conversion between the $\tilde {A}{ }^2B_2 \mbox{ and }\tilde {X}{ }^2A_1$ states and is a benchmark example of such barrierless reactions. We have applied time-resolved imaging to measure the time-evolution, angular and kinetic energy distributions of NO$^{+}$, NO$_{2}^{+}$ and photo electrons produced in pump-probe experiments using harmonics from a regeneratively amplified self-mode locked Ti:sapphire laser. Oscillations in the slow NO$^{+}$ and photoelectron signals are observed and are interpreted as measuring the energy level density of the coupled $\tilde {A}{ }^2B_2 \mbox{ and }\tilde {X}{ }^2A_1$ states close to the conical intersection. By using an optical pulse shaper we are able to manipulate the spectrum of the $\sim$400 nm excitation to create pulse sequences with which we can exert partial control over the coupling between the $\tilde {A}{ }^2B_2 \mbox{ and }\tilde {X}{ }^2A_1$ states.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.MAR.L26.4