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Updated: May 3, 2026

Submillisecond Conformational Changes in Proteins Resolved by Photothermal Beam Deflection
Published on: February 18, 2014
Conformer-resolved ultrafast chemical dynamics observed at ambient temperature
Zhengrong Wei1,2, Jesús González Vázquez3,4, Pedro Recio5
1School of Chemistry, Chemical Engineering and Biotechnology, and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
Abstract:
The nearly identical spectral features of conformers and their fast interconversion make tracking ultrafast chemical dynamics with conformational resolution at room temperature challenging. Here, we investigate the ionization-induced ultrafast dissociation dynamics of 1-iodopropane (1-C3H7I) conformers by high-resolution photoelectron-photoion coincidence spectroscopy, femtosecond extreme ultraviolet (XUV) transient absorption spectroscopy, and ab initio calculations. Vibrational wave packet dynamics obtained by monitoring the iodine 4d core-level transitions of 1-C3H7I+ [Formula: see text] 2E1/2 suggest rapid depopulation of the gauche conformer. Global analysis of the time-resolved XUV transient absorption spectra reveals simultaneous decay of 1-C3H7I+ [Formula: see text] 2E1/2 and growth of I (2P3/2), with time constants of 0.19 ± 0.03 and 1.4 ± 0.3 ps, attributed to C─I dissociation of the gauche and anti conformers, respectively. Extended multistate CASPT2 and relativistic state-averaged CASSCF calculations support this assignment. Our findings show that the conformational degree of freedom plays an important role in determining the outcome of chemical reactions even on ultrashort timescales.
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