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Title: Ultracold chemistry with alkali-metal–rare-earth molecules

Abstract

Here, a first principles study of the dynamics of 6Li( 2S) + 6Li 174Yb( 2Σ +) → 6Li 2( 1Σ +) + 174Yb( 1S) reaction is presented at cold and ultracold temperatures. The computations involve determination and analytic fitting of a three-dimensional potential energy surface for the Li 2 Yb system and quantum dynamics calculations of varying complexities, ranging from exact quantum dynamics within the close-coupling scheme, to statistical quantum treatment, and universal models. It is demonstrated that the two simplified methods yield zero-temperature limiting reaction rate coefficients in reasonable agreement with the full close-coupling calculations. The effect of the three-body term in the interaction potential is explored by comparing quantum dynamics results from a pairwise potential that neglects the three-body term to that derived from the full interaction potential. Inclusion of the three-body term in the close-coupling calculations was found to reduce the limiting rate coefficients by a factor of two. The reaction exoergicity populates vibrational levels as high as v = 19 of the 6Li 2 molecule in the limit of zero collision energy. Product vibrational distributions from the close-coupling calculations reveal sensitivity to inclusion of three-body forces in the interaction potential. In conclusion, the results indicate thatmore » a simplified model based on the long-range potential is able to yield reliable values of the total reaction rate coefficient in the ultracold limit but a more rigorous approach based on statistical quantum or quantum close-coupling methods is desirable when product rovibrational distribution is required.« less

Authors:
 [1];  [2];  [2];  [1]; ORCiD logo [3];  [4];  [2];  [1]
  1. Temple University, Philadelphia, PA (United States)
  2. Univ. of Nevada, Las Vegas, NV (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. Instituto de Física Fundamental, IFF-CSIC, Madrid (Spain)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1471323
Alternate Identifier(s):
OSTI ID: 1181234
Report Number(s):
LA-UR-14-28770
Journal ID: ISSN 1050-2947; PLRAAN
Grant/Contract Number:  
AC52-06NA25396; 20140309ER
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review. A
Additional Journal Information:
Journal Volume: 91; Journal Issue: 1; Journal ID: ISSN 1050-2947
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; ultracold; cold; molecules; scattering; chemical reaction

Citation Formats

Makrides, C., Hazra, J., Pradhan, G. B., Petrov, A., Kendrick, Brian Kent, González-Lezana, T., Balakrishnan, N., and Kotochigova, S. Ultracold chemistry with alkali-metal–rare-earth molecules. United States: N. p., 2015. Web. doi:10.1103/PhysRevA.91.012708.
Makrides, C., Hazra, J., Pradhan, G. B., Petrov, A., Kendrick, Brian Kent, González-Lezana, T., Balakrishnan, N., & Kotochigova, S. Ultracold chemistry with alkali-metal–rare-earth molecules. United States. doi:10.1103/PhysRevA.91.012708.
Makrides, C., Hazra, J., Pradhan, G. B., Petrov, A., Kendrick, Brian Kent, González-Lezana, T., Balakrishnan, N., and Kotochigova, S. Tue . "Ultracold chemistry with alkali-metal–rare-earth molecules". United States. doi:10.1103/PhysRevA.91.012708. https://www.osti.gov/servlets/purl/1471323.
@article{osti_1471323,
title = {Ultracold chemistry with alkali-metal–rare-earth molecules},
author = {Makrides, C. and Hazra, J. and Pradhan, G. B. and Petrov, A. and Kendrick, Brian Kent and González-Lezana, T. and Balakrishnan, N. and Kotochigova, S.},
abstractNote = {Here, a first principles study of the dynamics of 6Li(2S) + 6Li174Yb(2Σ+) → 6Li2(1Σ+) + 174Yb(1S) reaction is presented at cold and ultracold temperatures. The computations involve determination and analytic fitting of a three-dimensional potential energy surface for the Li2 Yb system and quantum dynamics calculations of varying complexities, ranging from exact quantum dynamics within the close-coupling scheme, to statistical quantum treatment, and universal models. It is demonstrated that the two simplified methods yield zero-temperature limiting reaction rate coefficients in reasonable agreement with the full close-coupling calculations. The effect of the three-body term in the interaction potential is explored by comparing quantum dynamics results from a pairwise potential that neglects the three-body term to that derived from the full interaction potential. Inclusion of the three-body term in the close-coupling calculations was found to reduce the limiting rate coefficients by a factor of two. The reaction exoergicity populates vibrational levels as high as v = 19 of the 6Li2 molecule in the limit of zero collision energy. Product vibrational distributions from the close-coupling calculations reveal sensitivity to inclusion of three-body forces in the interaction potential. In conclusion, the results indicate that a simplified model based on the long-range potential is able to yield reliable values of the total reaction rate coefficient in the ultracold limit but a more rigorous approach based on statistical quantum or quantum close-coupling methods is desirable when product rovibrational distribution is required.},
doi = {10.1103/PhysRevA.91.012708},
journal = {Physical Review. A},
number = 1,
volume = 91,
place = {United States},
year = {2015},
month = {1}
}

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