Related Experiment Video
Updated: Jun 25, 2026

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−
Published on: July 27, 2018
Time-resolved velocity map ion imaging study of NH(3) photodissociation
Kym L Wells1, Gareth Perriam, Vasilios G Stavros
1Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom.
Abstract:
Following excitation of the A state nu(2) (')=4 mode in ammonia, we show how the time scale to dissociation of the N-H bond depends on the internal energy imparted to the NH(2) photofragment. Using a combination of femtosecond pump/probe spectroscopy and velocity map ion imaging techniques, the time and energy resolved H-atom elimination can be directly related to the nonadiabatic nature of the photodissociation for high kinetic energy H atoms with evidence for adiabatic dynamics to dissociation giving the lowest energy H atoms. Extrapolation of the time scales for dissociation versus internal energy of the NH(2) photofragment implies that dissociation to the vibrationless ground state of NH(2) occurs in <50 fs, in very good agreement with frequency resolved measurements. The anisotropy of the H fragments with the highest kinetic energies seems to also suggest that the NH(2) partner fragment comes off with very low rotational excitation.
Related Concept Videos
Mass Spectrometry of Amines
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
¹H NMR of Labile Protons: Temporal Resolution
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the specific...
Relative Velocity in Two Dimensions
IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
NMR Spectroscopy Of Amines

