Geometric phase effects in the ultracold H + H2reaction.
The H3system has served as a prototype for geometric phase (GP) effects in bimolecular chemical reactions for over three decades. Despite a large number of theoretical and experimental efforts, no conclusive evidence of GP effects in the integral cross section or reaction rate has been presented until recently [B. Kendrick et al., Phys. Rev. Lett. 115, 153201 (2015)]. Here we report a more detailed account of GP effects in the H + H2(v = 4, j = 0) → H + H2(v', j') (para-para) reaction rate coefficients for temperatures between 1 μK (8.6 × 10-11eV) and 100 K (8.6 × 10-3eV). The GP effect is found to persist in both vibrationally resolved and total rate coefficients for collision energies up to about 10 K. The GP effect also appears in rotationally resolved differential cross sections leading to a very different oscillatory structure in both energy and scattering angle. It is shown to suppress a prominent shape resonance near 1 K and enhance a shape resonance near 8 K, providing new experimentally verifiable signatures of the GP effect in the fundamental hydrogen exchange reaction. The GP effect in the D + D2and T + T2reactions is also examined in the ultracold limit and its sensitivity to the potential energy surface is explored.
Theoretical Division (T-1, MS B221), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
B K
BK
Kendrick
Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154, USA.
Jisha
J
Hazra
Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154, USA.
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N
Balakrishnan