摘要:

In this paper we assess and synthesize the available information on the cross sections and the rate coefficients for collisional interactions of trifluoromethane (CHF3) with electrons in an effort to build a database on electronic and ionic collision processes that will aid the understanding of the behavior of CHF3in its use in manufacturing semiconductor devices and other applications. The limited data on the total and partial electron impact ionization cross sections, total and partial cross sections for electron impact dissociation of CHF3into neutral species, electron-impact induced line and continuous light emission from CHF3, negative ion states of CHF3, and the energetics of ionization, dissociation, and attachment are summarized and discussed. Besides some recent unpublished measurements of the total electron scattering cross section below 20 eV, to our knowledge no measurements are available of the cross sections of any of the electron scattering processes (elastic, momentum, vibrational, inelastic, etc.) or the electron transport, attachment, and ionization coefficients. While the available information is meager, the synthesis of the existing knowledge and the background information provided in the paper can be helpful for modeling plasma reactors. Clearly, more measurements and calculations are needed of the cross sections for virtually all fundamental electron impact processes for this plasma processing gas. Measurements of the transport, attachment, and ionization coefficients over wide ranges of the density reduced electric field are also needed. ©1997 American Institute of Physics and American Chemical Society.Key words:attachment; CHF3;cross sections; dissociation; electron scattering; emission; fluoroform; ionization; transport; trifluoromethane.

ISSN:0047-2689    

DOI:10.1063/1.556004

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The available microwave and millimeter-wave spectra of methanol, CH3OH, and its most abundant isotopomer,13CH3OH, are critically reviewed and supplemented with spectral frequency calculations derived from rotation-internal rotation analyses. For both species, global analyses of the torsional ground state,&ngr;t=0, and the first excited torsional state,&ngr;t=1, have been carried out in which all observed spectral lines are reproduced to within their measurement uncertainties. References are given for all data included. The primary objective of this review is to provide radio astronomers with complete spectral coverage of rotational transitions from 500 MHz to 1 THz, including the lower state energy and line strength for each transition, over the range in rotational quantum numberJfrom 0 to 26. ©1997 American Institute of Physics and American Chemical Society.Key words:Internal rotation (or torsion); interstellar molecule; isotopomer; line strength; methanol; microwave and millimeter-wave spectra; radio astronomy; rotational transitions.

ISSN:0047-2689    

DOI:10.1063/1.556005

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The experimental techniques and the prediction procedures for the determination or evaluation of the vapor pressure of environmentally relevant organic compounds are described; with 259 references examined. For each of them the characteristics of precision and accuracy are given, when available from the literature. The experimental methods are classified as “direct” and “indirect.” The first class includes all those which can measure directly the vapor pressure, while the second concerns those which need “known” vapor pressures of reference compounds for the calibration. Prediction methods are based on the application of the Clapeyron–Clausius equation or on the quantitative structure-property relationships. Also correlation methods require a suitable calibration. The vapor pressures at ambient temperature for several polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and furans, selected pesticides, and some reference compounds are tabulated together with the vapor pressure equations and the enthalpy values in the temperature range of measurement. A critical comparison, based on a statistical analysis of the data obtained with different methods and derived from 152 references, is also carried out. ©1996 American Institute of Physics and American Chemical Society.

ISSN:0047-2689    

DOI:10.1063/1.556006

出版商:AIP    

年代:1997

数据来源: AIP