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Title: Simplicity beneath Complexity: Counting Molecular Electrons Reveals Transients and Kinetics of Photodissociation Reactions

Abstract

Time-resolved pump-probe gas phase X-ray scattering signals, extrapolated to zero momentum transfer, provide a measure of the number of electrons in a system, an effect that arises from the coherent addition of elastic scattering from the electrons. This allows for the identification of reactive transients and the determination of the chemical reaction kinetics without the need for extensive scattering simulations or complicated inversion of scattering data. We examine the photodissociation reaction of trimethyl amine, and identify two reaction paths upon excitation to the 3p state at 200 nm: a fast dissociation path out of the 3p state to the dimethyl amine radical (16.6±1.2%), and a slower dissociation via internal conversion to the 3s state (83.4±1.2%). The time constants for the two reactions are 640±130 fs and 74±6 ps, respectively. In addition, it is found that the transient dimethyl amine radical has a N-C bond length of 1.45±0.02 Å and a CNC bond angle of 118°±4°.

Authors:
 [1]
  1. SLAC National Accelerator Lab., Menlo Park, CA (United States). Linac Coherent Light Source (LCLS)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1500111
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Program Document
Country of Publication:
United States
Language:
English

Citation Formats

Minitti, Michael P. Simplicity beneath Complexity: Counting Molecular Electrons Reveals Transients and Kinetics of Photodissociation Reactions. United States: N. p., 2019. Web.
Minitti, Michael P. Simplicity beneath Complexity: Counting Molecular Electrons Reveals Transients and Kinetics of Photodissociation Reactions. United States.
Minitti, Michael P. Tue . "Simplicity beneath Complexity: Counting Molecular Electrons Reveals Transients and Kinetics of Photodissociation Reactions". United States. https://www.osti.gov/servlets/purl/1500111.
@article{osti_1500111,
title = {Simplicity beneath Complexity: Counting Molecular Electrons Reveals Transients and Kinetics of Photodissociation Reactions},
author = {Minitti, Michael P},
abstractNote = {Time-resolved pump-probe gas phase X-ray scattering signals, extrapolated to zero momentum transfer, provide a measure of the number of electrons in a system, an effect that arises from the coherent addition of elastic scattering from the electrons. This allows for the identification of reactive transients and the determination of the chemical reaction kinetics without the need for extensive scattering simulations or complicated inversion of scattering data. We examine the photodissociation reaction of trimethyl amine, and identify two reaction paths upon excitation to the 3p state at 200 nm: a fast dissociation path out of the 3p state to the dimethyl amine radical (16.6±1.2%), and a slower dissociation via internal conversion to the 3s state (83.4±1.2%). The time constants for the two reactions are 640±130 fs and 74±6 ps, respectively. In addition, it is found that the transient dimethyl amine radical has a N-C bond length of 1.45±0.02 Å and a CNC bond angle of 118°±4°.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {1}
}

Program Document:
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