@article{d572454c893b4b878bd3abbdfb4ad76d,
title = "Photodissociation transition states characterized by chirped pulse millimeter wave spectroscopy",
abstract = "The 193-nm photolysis of CH2CHCN illustrates the capability of chirped-pulse Fourier transform millimeter-wave spectroscopy to characterize transition states. We investigate the HCN, HNC photofragments in highly excited vibrational states using both frequency and intensity information. Measured relative intensities of J = 1–0 rotational transition lines yield vibrational-level population distributions (VPD). These VPDs encode the properties of the parent molecule transition state at which the fragment molecule was born. A Poisson distribution formalism, based on the generalized Franck–Condon principle, is proposed as a framework for extracting information about the transition-state structure from the observed VPD. We employ the isotopologue CH2CDCN to disentangle the unimolecular 3-center DCN elimination mechanism from other pathways to HCN. Our experimental results reveal a previously unknown transition state that we tentatively associate with the HCN eliminated via a secondary, bimolecular reaction.",
keywords = "Chirped-pulse millimeter-wave spectroscopy, Photolysis, Transition state, Vibrational population distribution, Vibrational satellites",
author = "Kirill Prozument and Baraban, {Joshua H.} and {Bryan Changala}, P. and {Barratt Park}, G. and Shaver, {Rachel G.} and Muenter, {John S.} and Klippenstein, {Stephen J.} and Chernyak, {Vladimir Y.} and Field, {Robert W.}",
note = "Funding Information: ACKNOWLEDGMENTS. We thank Dr. Georg Mellau for his advice on the assignments of the v2 = 12 and 14 vibrational levels of HCN. K.P. thanks Branko Ruscic for helpful discussions. We thank the Department of Energy (grant DEFG0287ER13671) for providing primary support of this work (equipment and personnel support for R.G.S.), the Petroleum Research Fund (grant 50650-ND6) for support of K.P., and the National Science Foundation (grant 1126380) for equipment support. K.P. and S.J.K. acknowledge the support by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences under contract DE-AC02-06CH11357. V.Y.C. was supported by the US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, Condensed Matter Theory Program. Funding Information: We thank Dr. Georg Mellau for his advice on the assignments of the v2 = 12 and 14 vibrational levels of HCN. K.P. thanks Branko Ruscic for helpful discussions. We thank the Department of Energy (grant DEFG0287ER13671) for providing primary support of this work (equipment and personnel support for R.G.S.), the Petroleum Research Fund (grant 50650-ND6) for support of K.P., and the National Science Foundation (grant 1126380) for equipment support. K.P. and S.J.K. acknowledge the support by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences under contract DE-AC02-06CH11357. V.Y.C. was supported by the US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, Condensed Matter Theory Program. Publisher Copyright: {\textcopyright} 2020 National Academy of Sciences. All rights reserved.",
year = "2020",
month = jan,
day = "7",
doi = "10.1073/pnas.1911326116",
language = "English",
volume = "117",
pages = "146--151",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
publisher = "National Academy of Sciences",
number = "1",
}