We present a theoretical study of elastic and rotationally inelastic collisions of NH3 and ND3 with rare gas atoms (He, Ne, Ar, Kr, Xe) at low energy. Quantum close-coupling calculations have been performed for energies between 0.001 and 300 cm(-1). We focus on collisions in which NH3 is initially in the upper state of the inversion doublet with j = 1, k = 1, which is the most relevant in an ex...

Introduction: A major objective of GENESIS is to constrain the present day solar wind (SW) Ar, Kr, and Xe isotopic and elemental compositions by direct measurements of SW irradiated artificial samples [1]. Due to the low abundances of heavy noble gases in the SW, until now these compositions could only be inferred from regolith samples which were irradiated by the SW over large time spans [e.g....

Rotational isomerization of acetic acid (CH3COOH) is studied in Ar, Kr, and Xe matrices. The light-induced trans-->cis reaction is promoted using resonant excitation of a number of modes in the 3500-7000 cm(-1) region, and the quantum yields for this process are measured for various acetic acid isotopologues and matrix materials. For excitation of acetic acid at energies above the predicted iso...

Gas ratios in air withdrawn from polar firn (snowpack) show systematic enrichments of Ne/N2, O2/N2 and Ar/N2, in the firn–ice transition region where bubbles are closing off. Air from the bubbles in polar ice is correspondingly depleted in these ratios, after accounting for gravitational effects. Gas in the bubbles becomes fractionated during the process of bubble close-off and fractionation ma...

Secondary electron emission yield values for rare-gas particles (He, Ne, Ar, Kr, and Xe ions of atoms and molecules, metastable atoms, and excimers) of MgO deposited under optimum conditions for the highest values were calculated assuming the Auger transitions between the valence band, and the (oxygen ion vacancy + two electrons) and + (oxygen ion vacancy + one electron) centers in the MgO surf...