High resolution threshold photodetachment spectroscopy of negative ions

Negative ions, mass selection, and photoelectrons

“…Additional concepts, such as time-of-flight mass separators, supersonic molecular beams, and laser desorption (Posey et al, 1986;Ganteför et al, 1988;Hugh et al, 1989;Hoe et al, 1990;Taylor et al, 1992;Cha et al, 1992) opened new options to study systems that were hardly accessible before, such as larger molecules, and atomic and molecular clusters. Finally, the development of the zero-kinetic-energy photoelectron spectroscopy (ZEKE) for anions (Kitsopoulos et al, 1989;Ganteför et al, 1990;Drechsler et al, 1994b) based on the cation 4 neutral ZEKE method (Müller-Dethlefs et al, 1984a;) allowed one to push the energy resolution to the magic limit of 1 cm Ϫ1 . For detailed in-depth information on photodetachment and attachment experiments and data, we refer to review articles such as (Illenberger & Momigny, 1992;Christodoulides et al, 1984;Hotop & Lineberger, 1975;Janousek & Brauman, 1979).…”

Threshold photodetachment spectroscopy of C−5

“…8 Table I, are aided by ab initio calculated vibrational frequencies" and the infrared absorption work on C 5 by Amano and co-workers. 4 We observe transitions to the v' = 1 level of the V 2 symmetric stretch and to the v' = 2 levels of the V 5 , V 6 , and V 7 bending modes (since the bending modes are not totally symmetric, only transitions to even levels from the v" = 0 anion level can occur 7 ) .…”

Threshold photodetachment spectroscopy of negative ions

“…29 In both instruments, Si 2 -anions are generated by laser vaporization. The anions are mass-selected in a timeof-flight mass spectrometer.…”

“…For the photodetachment of an atomic negative ion, he found that (29) where Elb is the threshold energy, and I is the angular momentum of the ejected photoelectron. This law was derived for atoms and it was assumed that long range forces govern the shape of the cross section near threshold.…”