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Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate
Published on: September 13, 2019
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Matrix Isolation Spectroscopy and Nuclear Spin Conversion of Propyne Suspended in Solid Parahydrogen
A I Strom1, A Gutiérrez-Quintanilla2,3, M Chevalier2
1Department of Chemistry, University of Wyoming, Laramie 82071-3838, Wyoming, United States.
The Journal of Physical Chemistry. A
|May 14, 2020
Summary
Parahydrogen quantum solids enable study of propyne
Area of Science:
- Quantum solids
- Molecular spectroscopy
- Chemical kinetics
Background:
- Parahydrogen (pH2) quantum solids serve as matrices for molecular studies.
- Nuclear spin conversion (NSC) kinetics are crucial for understanding molecular dynamics.
Purpose of the Study:
- To assign the rovibrational spectrum of propyne (CH3CCH) using its NSC kinetics in solid pH2.
- To investigate the rotational dynamics of propyne within a pH2 matrix.
Main Methods:
- Matrix isolation spectroscopy in solid parahydrogen.
- Analysis of rovibrational bands (parallel and perpendicular).
- Intensity-intensity correlation plots for line strength determination.
Main Results:
- Propyne's end-over-end rotation is quenched, but K-rotation persists, albeit hindered.
- NSC kinetics follow first-order reversible kinetics with a 287(7) min time constant at 1.7 K.
- Relative line strengths were determined, allowing estimation of the ground vibrational state effective A″ constant.
Conclusions:
- Solid pH2 is a valuable matrix for studying hindered rotation and NSC kinetics.
- The study successfully assigned propyne's rovibrational spectrum and provided insights into its rotational behavior.
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