Hunt for geometric phase effects in H + HD → HD(v′, j′) + H

Abstract

An attempt has been made to measure the theoretically predicted manifestation of a geometric phase in the differential cross section for the H + HD → HD(v' = 2, j' = 5) + H reaction at a center-of-mass collision energy of 1.44 eV (33.2 kcal∕mol). Minute oscillatory differences between calculated differential cross sections that take into account and ignore the effect of geometric phase have proven to be beyond our experimental resolution in spite of the collection of more than 44,000 ions.

Geometric phase effects in the ultracold D + HD $ \rightarrow $ D + HD and D + HD $\leftrightarrow $ H + D2reactions

“…GP effects in molecular spectra have been reported in several theoretical treatments [4,12,[28][29][30][31][32][33][34][35][36][37][38] and it has been confirmed experimentally for the molecules Cu 3 , [39] Li 3 , [40] and Na 3 [41]. In stark contrast, the experimental measurement of a GP effect in molecular scattering has continued to be elusive to this day [42,43]. The first theoretical prediction of a GP effect in scattering was made by Mead for the H + H 2 system [44].…”

“…At energies above the conical intersection, large GP effects on the DCSs were reported which give rise to broader bimodal features [61][62][63]. Unfortunately, a recent experimental effort was unable to resolve the GP oscillations in the DCSs for the H + HD  H + HD reaction at energies below the conical intersection [42,43]. No significant GP effects have been reported in the integral cross sections (or reaction rate coefficients) at any thermal energy.…”

Perspective: Ultracold molecules and the dawn of cold controlled chemistry

“…263 This was further confirmed by Althorpe and collaborators 265,273,274 who employed a time-dependent quantum method to solve the Schrödinger equation. Recent combined experimental and theoretical investigations by Jankunas et al 271,272 was unsuccessful in confirming GP effects in the H + HD and H + D 2 reactions. In all these studies, the primary reason for the inability to observe GP effects appears to be the partial wave summation, where contributions from even and odd partial waves cancel the GP effect.…”

“…269,270 However, its effect on chemical reaction rates has long eluded experimental detection and it continues to be an active topic of experimental and theoretical studies. 271,272 The H + H 2 reaction and its isotopologues have long served as benchmark systems for experimental verification of the GP effect in chemical reactions. [263][264][265][271][272][273][274][275] All of these experiments that probe GP effects involve molecules in low initial vibrational quantum numbers (mostly the v = 0 vibrational level) and high kinetic energies for the relative motion.…”

A scheme for a single molecule phase-shift gate in a solid matrix

“…This property is interesting not only from a fundamental viewpoint [2][3][4][5][6][7][8][9][10][11][12] but also for its applications. [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] Since a quantum system is inevitably coupled to the environment, the investigation of geometric phases in open quantum systems has also attracted considerable attention. [7][8][9][10][11][12][28][29][30][31][32][33][34][35][36][37][38][39][40] The phase-shift gate as a quantum logic operator is an important element of quantum computation.…”