Low-level vibrational relaxation in single gas-surface encounters. Molecular structure, surface, and temperature effects

Abstract

Direct measurement of the vibrational temperatures attained by different gases after single encounters with hot silica or platinum surfaces at T_S have been obtained by modulated-beam mass spectrometry. Vibrational energy accommodation coefficients a, for n-butane, n-octane, and 1-chlorobutane are smaller than one over both surfaces, slightly increase with molecular size or polarity, and are nearly independent of T_S between 350 and 700 K. Relaxation is more efficient on platinum.

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