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Title: Geometric phase effects in the ultracold D + HD $$ \rightarrow $$ D + HD and D + HD $$\leftrightarrow $$ H + D 2 reactions

The results of accurate quantum reactive scattering calculations for the D + HD(v = 4, j = 0) $$\to $$ D + HD($$v^{\prime} $$, $$j^{\prime} $$), D + HD(v = 4, j = 0) $$\to $$ H + D2($$v^{\prime} $$, $$j^{\prime} $$) and H + D2(v = 4, j = 0) $$\to $$ D + HD($$v^{\prime} $$, $$j^{\prime} $$) reactions are presented for collision energies between $$1\,\mu {\rm{K}}$$ and $$100\,{\rm{K}}$$. The ab initio BKMP2 PES for the ground electronic state of H3 is used and all values of total angular momentum between $J=0-4$ are included. The general vector potential approach is used to include the geometric phase. The rotationally resolved, vibrationally resolved, and total reaction rate coefficients are reported as a function of collision energy. Rotationally resolved differential cross sections are also reported as a function of collision energy and scattering angle. Large geometric phase effects appear in the ultracold reaction rate coefficients which result in a significant enhancement or suppression of the rate coefficient (up to 3 orders of magnitude) relative to calculations which ignore the geometric phase. The results are interpreted using a new quantum interference mechanism which is unique to ultracold collisions. Significant effects of the geometric phase also appear in the rotationally resolved differential cross sections which lead to a very different oscillatory structure in both energy and scattering angle. Several shape resonances occur in the 1–$$10\,{\rm{K}}$$ energy range and the geometric phase is shown to significantly alter the predicted resonance spectrum. The geometric phase effects and ultracold rate coefficients depend sensitively on the nuclear spin. Furthermore, experimentalists may be able to control the reaction by the selection of a particular nuclear spin state.
Authors:
ORCiD logo [1] ;  [2] ;  [2]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Univ. of Nevada, Las Vegas, NV (United States)
Publication Date:
Report Number(s):
LA-UR-16-25136
Journal ID: ISSN 1367-2630; TRN: US1701141
Grant/Contract Number:
AC52-06NA25396; 20140309ER
Type:
Published Article
Journal Name:
New Journal of Physics
Additional Journal Information:
Journal Volume: 18; Journal Issue: 12; Journal ID: ISSN 1367-2630
Publisher:
IOP Publishing
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Laboratory Directed Research and Development (LDRD) Program
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; Inorganic and Physical Chemistry; Ultracold chemistry, cold molecules, geometric phase
OSTI Identifier:
1336493
Alternate Identifier(s):
OSTI ID: 1336494; OSTI ID: 1345159