Vibrationally elastic scattering cross section of water vapor by electron impact

Abstract

Absolute di6'erential cross sections of electrons vibrationally elastically scattered from water vapor have been measured at room temperature by electron impact. A modulated crossed-beam method was used. The energy and angular range covered were from 2.2 to 20 eV and from 15' to 150', respectively. Strong backward scattering has been observed as predicted by theory, The measured integrated and momentum-transfer cross sections are generally larger than others in the literature by 50%.

Low Energy Elastic Differential Electron Scattering fromH2O

“…Figure 1 shows our DCSs at E 0 values of 4, 6, and 20 eV. At E 0 4 eV, we observe best agreement with the theory of Varella et al [23] using the successful Schwinger multichannel model, especially at 60 , and observe good agreement with Cho et al [3] and Shyn and Cho [13]. Our DCSs are in excellent shape agreement, but consistently higher than other experiments.…”

“…At E 0 6 eV we note that our DCSs are in reasonable quantitative agreement only with Shyn and Cho [13] at < 60 , being higher by about 40% on average with other measurements. Agreement with Scattering Angle (deg) [12], ᭛ Shyn and Cho [13], Johnstone and Newell [14], Cho et al [3]. Theory: (solid line) Schwinger multichannel method with polarized pseudostates and with Born closure, Varella et al [23].…”

Analytic Cross Sections for Electron Collisions With Co, Co2, and H2o Relevant to Edge Plasma Impurities

“…All the measurements except for Ref. [58] [63], Katase et al [64], and Shyn and Cho [65]. Two recent measurements have been reported.…”

Measurements of differential cross sections in the backscattering region

“…Here, the agreement among experimental data is reasonable within the stated uncertainties up to about 1201. Above 1201, the results of Shyn and Cho (1987) differ from those of Cho et al (2004b) by almost 100%. The results of theoretical calculations (Okamoto et al, 1993;Machado et al, 1995), particularly those of Gianturco et al (1998) (the coupled-channel calculations in the body-fixed frame with the exact static-exchange potential) and the most recent results of the R-matrix calculation (Faure et al, 2004) follow the experimental results over the entire angular range.…”

“…There is a wealth of information available in the literature on the elastic scattering of electrons in the energy range from 0.5 to 400 eV and covering angular range from 101 to 1561 (Danjo and Nishimura, 1985;Shyn and Cho, 1987;Johnstone and Newell, 1991). Recently, Cho et al (2004b) have obtained DCSs up to 1801 in the energy range from 4 to 50 eV using the magnetic angle-changing technique.…”