Journal of Research of the National Bureau of Standards Section A Physics and Chemistry · 1964 · 81 citations · 5 references
A windowless vacuum ultraviolet monochromator and mass spectrometer are combined for the study of photoionization processes in the energy range 2000 to 600 A (6 to 21 eV). Details of the apparatus and techniques of operation are given and results are reported for an initial study of acetylene, acetylene-<i>d</i> <sub>2</sub>, benzene, and benzene-<i>d</i> <sub>6</sub>. Ionization energies of 11.406 and 11.416 eV are obtained for the 1<i>π<sub>u</sub></i> electron of C<sub>2</sub>H<sub>2</sub> and C<sub>2</sub>D<sub>2</sub>, respectively. Vibrational levels of the ground state of the ion are observed with quantum intervals of 1855 cm<sup>-1</sup>(C<sub>2</sub>H<sub>2</sub>) and 1775 cm<sup>-1</sup>(C<sub>2</sub>D<sub>2</sub>). Ionization energies for the <i>e</i> <sub>1</sub> <i><sub>g</sub></i> (<i>π</i>) electron of C<sub>6</sub>H<sub>6</sub> and C<sub>6</sub>D<sub>6</sub> are determined to be 9.24<sub>2</sub> and 9.24<sub>5</sub> eV, respectively. Quantum intervals for vibrational levels of the ground state ions are apparently equal for the two isotopic molecules and estimated to be 800 cm<sup>-1</sup>. A second onset of ionization is observed at 11.5<sub>3</sub> eV for C<sub>6</sub>H<sub>6</sub> and at 11.5<sub>9</sub> eV for C<sub>6</sub>D<sub>6</sub>. Results agree well with spectroscopic data.
5
Incoherent Inelastic Neutron Scattering and Self-Diffusion
Robert Zwanzig · Physical Review · 1964 · 20 citations
Cross Section, Engineering, Physics +11