Electron attachment to POCl 3. II. Dependence of the attachment rate coefficients on gas and electron temperature

Abstract

Rate coefficients for attachment of electrons to POCl 3 have been measured in two FALP (flowing-afterglow Langmuir-probe) apparatuses, extending the temperature range of earlier experiments. The results for equal gas and electron temperatures are compared with data for independently varied temperatures. An analysis of the rate coefficients in terms of electron-polar target capture theory leads to empirical electron–phonon coupling factors which are markedly smaller than unity. These factors depend on the electron energy but do not seem to depend on the gas temperature, which is in contrast to observations made for the electron attachment to SF 6. Besides s-wave attachment, contributions from higher partial waves are analyzed and suggested to contribute to some extent. Attachment cross sections and specific rate constants for electron autodetachment are finally constructed in a way which is consistent with the experimental attachment rate coefficients. Autodetachment is shown to be negligible compared to dissociation of POCl 3 − which is analyzed in a subsequent publication.