Photoemission and electron mean free paths in liquid formamide in the vacuum UV

Journal Article · Tue Jun 01 04:00:00 EDT 1982 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.442915· OSTI ID:5594364

Birkhoff, R D; Heller, Jr, J M; Painter, L R; Ashley, J C; Hubbell, Jr, H H

Our apparatus has been modified to permit measurements of absolute photoemission as well as reflectance of liquids in the vacuum UV. Photon fluxes are determined by filling the tandem ion chambers with argon. An electrometer is connected to the sample cup, which must be properly biased, to read electron currents leaving the cup. After argon ion drift into the cup is taken into account, the yields of photoelectrons per incident photon and per absorbed photon are obtained. These yield curves for liquid formamide (HCONH/sub 2/) are similar to each other over the energy range studied (16--25 eV). They are nearly constant between 16 and 18 eV at 13.5% and decline toward higher energies. The surface and volume plasmon energies for formamide are near 19 and approximately 27 eV, respectively. We suggest that photoelectron excitation of surface plasmons may enhance the photoemission yield, while excitation of volume plasmons may reduce it. Values of electron mean free path derived from the yields and a simple three-step model for photoemission are found to be about two to three times larger than predicted by theory.

• Research Organization: Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37916
• OSTI ID: 5594364
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 76:11; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
AMIDES
ELECTROMAGNETIC RADIATION
EMISSION
FAR ULTRAVIOLET RADIATION
FLUIDS
FORMAMIDE
LIQUIDS
OPTICAL PROPERTIES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOEMISSION
PHYSICAL PROPERTIES
RADIATIONS
SECONDARY EMISSION
SPECTRAL REFLECTANCE
SURFACE PROPERTIES
ULTRAVIOLET RADIATION