Anomalous laser-induced ionization rates of molecules and rare-gas atoms

Journal Article · Tue Dec 15 04:00:00 EST 2009 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.80.063420· OSTI ID:21352387

Bettis, Jerry Ray ^[1]

---

1. 5701 Woodlake Drive, Stillwater, Oklahoma 74074 (United States)

Electron tunnel ionization is considered as the mechanism for producing free electrons in gases under laser radiation. The Keldysh result and the Ammosov-Delone-Krainov (ADK) formulation are amended by considering the excess forces due to the interaction of the electric field of the laser with the electron cloud in a simple mass-on-a-spring approximation. The result of this excess force is a kinetic energy that is directed along the polarization vector of the laser field and an induced potential energy that are proposed as a determining factor in electron tunnel ionization. Relative ionization rates for various pairs of gases are calculated and compared with reported figures. Comparisons were made between several combinations of O{sub 2}, Xe, Ar, N{sub 2}, Cl{sub 2}, H{sub 2}, CO, Kr, NO, F{sub 2}, and D{sub 2}. Predicted ratios of ionization rates between pairs of gases are compared to ADK predictions. Apparently anomalous ionization rates of O{sub 2}, D{sub 2}, and H{sub 2} are explained. A simple expression is developed that reveals why the ionization rate of Xe is about an order of magnitude larger than that of O{sub 2} even though their ionization potentials are nearly identical; why CO is only about half that of Kr even though their ionization potentials are nearly the same; why the ratio of O{sub 2} to O is about ten times larger than predicted by ADK; and why the ratio of NO to Xe is about an order of magnitude less than predicted by ADK.

• OSTI ID: 21352387
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 6 Vol. 80; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ARGON
ATOM COLLISIONS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHLORINE
COLLISIONS
ELECTRIC FIELDS
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
FLUIDS
FLUORINE
GASES
HALOGENS
HELIUM
HYDROGEN
IONIZATION
IONIZATION POTENTIAL
KRYPTON
LASER RADIATION
LEPTONS
MOLECULE COLLISIONS
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHOTOIONIZATION
PHOTON COLLISIONS
PHOTON-ATOM COLLISIONS
PHOTON-MOLECULE COLLISIONS
PHYSICAL PROPERTIES
POLARIZABILITY
RADIATIONS
RARE GASES
TUNNEL EFFECT
XENON