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Title: Direct observation of bimolecular reactions of ultracold KRb molecules

Abstract

Femtochemistry techniques have been instrumental in accessing the short time scales necessary to probe transient intermediates in chemical reactions. In this study, we took the contrasting approach of prolonging the lifetime of an intermediate by preparing reactant molecules in their lowest rovibronic quantum state at ultralow temperatures, thereby markedly reducing the number of exit channels accessible upon their mutual collision. Using ionization spectroscopy and velocity-map imaging of a trapped gas of potassium-rubidium (KRb) molecules at a temperature of 500 nanokelvin, we directly observed reactants, intermediates, and products of the reaction 40 K 87 Rb + 40 K 87 Rb → K 2 Rb 2 * → K 2 + Rb 2 . Beyond observation of a long-lived, energy-rich intermediate complex, this technique opens the door to further studies of quantum-state–resolved reaction dynamics in the ultracold regime.

Authors:
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Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1576076
Resource Type:
Published Article
Journal Name:
Science
Additional Journal Information:
Journal Name: Science Journal Volume: 366 Journal Issue: 6469; Journal ID: ISSN 0036-8075
Publisher:
American Association for the Advancement of Science (AAAS)
Country of Publication:
United States
Language:
English

Citation Formats

Hu, M. -G., Liu, Y., Grimes, D. D., Lin, Y. -W., Gheorghe, A. H., Vexiau, R., Bouloufa-Maafa, N., Dulieu, O., Rosenband, T., and Ni, K. -K. Direct observation of bimolecular reactions of ultracold KRb molecules. United States: N. p., 2019. Web. doi:10.1126/science.aay9531.
Hu, M. -G., Liu, Y., Grimes, D. D., Lin, Y. -W., Gheorghe, A. H., Vexiau, R., Bouloufa-Maafa, N., Dulieu, O., Rosenband, T., & Ni, K. -K. Direct observation of bimolecular reactions of ultracold KRb molecules. United States. doi:10.1126/science.aay9531.
Hu, M. -G., Liu, Y., Grimes, D. D., Lin, Y. -W., Gheorghe, A. H., Vexiau, R., Bouloufa-Maafa, N., Dulieu, O., Rosenband, T., and Ni, K. -K. Thu . "Direct observation of bimolecular reactions of ultracold KRb molecules". United States. doi:10.1126/science.aay9531.
@article{osti_1576076,
title = {Direct observation of bimolecular reactions of ultracold KRb molecules},
author = {Hu, M. -G. and Liu, Y. and Grimes, D. D. and Lin, Y. -W. and Gheorghe, A. H. and Vexiau, R. and Bouloufa-Maafa, N. and Dulieu, O. and Rosenband, T. and Ni, K. -K.},
abstractNote = {Femtochemistry techniques have been instrumental in accessing the short time scales necessary to probe transient intermediates in chemical reactions. In this study, we took the contrasting approach of prolonging the lifetime of an intermediate by preparing reactant molecules in their lowest rovibronic quantum state at ultralow temperatures, thereby markedly reducing the number of exit channels accessible upon their mutual collision. Using ionization spectroscopy and velocity-map imaging of a trapped gas of potassium-rubidium (KRb) molecules at a temperature of 500 nanokelvin, we directly observed reactants, intermediates, and products of the reaction 40 K 87 Rb + 40 K 87 Rb → K 2 Rb 2 * → K 2 + Rb 2 . Beyond observation of a long-lived, energy-rich intermediate complex, this technique opens the door to further studies of quantum-state–resolved reaction dynamics in the ultracold regime.},
doi = {10.1126/science.aay9531},
journal = {Science},
number = 6469,
volume = 366,
place = {United States},
year = {2019},
month = {11}
}

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DOI: 10.1126/science.aay9531

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