Millard H. Alexander

Spectroscopic observation of resonances in the F + H ₂ reaction

Science · 2015-07-30 · 112 citations

Photodetachment spectroscopy of the FH2(-) and FD2(-) anions allows for the direct observation of reactive resonances in the benchmark reaction F + H2 → HF + H. Using cooled anion precursors and a high-resolution electron spectrometer, we observe several narrow peaks not seen in previous experiments. Theoretical calculations, based on a highly accurate F + H2 potential energy surface, convincingly assign these peaks to resonances associated with quasibound states in the HF + H and DF + D product…

Enhanced reactivity of fluorine with para-hydrogen in cold interstellar clouds by resonance-induced quantum tunnelling

Nature Chemistry · 2019-06-24 · 60 citations

Resonances in rotationally inelastic scattering of NH3 and ND3 with H2

The Journal of Chemical Physics · 2015-07-28 · 45 citations

We present theoretical studies on the scattering resonances in rotationally inelastic collisions of NH3 and ND3 molecules with H2 molecules. We use the quantum close-coupling method to compute state-to-state integral and differential cross sections for the NH3/ND3-H2 system for collision energies between 5 and 70 cm(-1), using a previously reported potential energy surface [Maret et al., Mon. Not. R. Astron. Soc. 399, 425 (2009)]. We identify the resonances as shape or Feshbach resonances. To an…

Fine-structure relaxation of O(3P) induced by collisions with He, H and H2

Monthly Notices of the Royal Astronomical Society · 2017-11-10 · 38 citations

The excitation of fine-structure levels of O(3P) by collisions is an important cooling process in the interstellar medium (ISM). We investigate here spin–orbit (de-)excitation of O(3Pj, j = 0, 1, 2) induced by collisions with He, H and H2 based on quantum scattering calculations of the relevant rate coefficients in the 10–1000 K temperature range. The underlying potential energy surfaces are derived from highly correlated abinitio calculations. Significant differences were found with the rate co…

Hibridon: A program suite for time-independent non-reactive quantum scattering calculations

Computer Physics Communications · 2023 · 26 citations