Photoionization spectra of CH_3I and C_2H_5I perturbed by CF4 and c-C_4F_8: Electron scattering in halocarbon gases
Abstract
Photoionization spectra of CH_3I and C_2H_5I doped into perturber halocarbon gases CF4 (up to a perturber number density of 6.1 x 10^20 cm-3) and c-C_4F8 (up to a perturber number density of 2.42 x 10^19 cm-3) disclosed a red shift of the dopant autoionizing features that depends linearly on the perturber number density. From the perturber induced energy shifts of the dopant nd' Rydbergs (n = 9 - 14), the zero-kinetic-energy electron scattering lengths for CF4 and c-C_4F8 were found to be -0.176 nm and -0.593 nm, respectively. Since CF4 is transparent in the spectral region of interest, the scattering length of CF4 was also obtained from dopant absorption spectra using the perturber induced energy shifts of the nd (n = 9 - 14) as well as the nd' (n = 9 - 14) Rydbergs. The scattering length for CF4 resulting from these absorption measurements is -0.177 nm, which agrees well with that obtained from the photoionization measurements. To our best knowledge, these are the first measurements of zero-kinetic-energy electron scattering lengths for both CF4 and c-C_4F_8. [Work carried out at UW Synchrotron Radiation Center (NSF DMR 95-31009), and supported by LEQSF (1997-00)-RD-A-14.]
- Publication:
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APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts
- Pub Date:
- June 2000
- Bibcode:
- 2000APS..DMP..W508E