Collision processes of high Rydberg states in atomic lithium

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1981

OSTI ID:6265961

Shepard, C L

A thermal beam of lithium atoms emanating from a heated oven and excited to high Rydberg states by pulsed electron impact has been studied in order to determine the interaction mechanisms which occur in collisions between high Rydberg atoms and neutral ground state atoms and molecules. The rare-gas atoms and nonpolar molecules used as collision partners for the lithium high Rydberg atoms (Li*) were neon (Ne), krypton (Kr), hydrogen (H/sub 2/), deuterium (D/sub 2/), nitrogen (N/sub 2/), oxygen (O/sub 2/), carbon dioxide (CO/sub 2/), and methane (CH/sub 4/). In addition to these eight targets, 16 polar molecules with dipole moments ranging from 0.11 to 2.88 debye were also used as target gases: carbon monoxide (CO), nitric oxide (NO), nitrous oxide (N/sub 2/O), nitrogen dioxide (NO/sub 2/), propylene (C/sub 3/H/sub 6/), carbonyl sulfide (COS), propylamine (CA3H/sup 8/O), formic acid (CH/sub 2/O/sub 2/), sulfur dioxide (SO/sub 2/), ethanol (C/sub 2/H/sub 6/O), methanol (CH/sub 4/O), acetone (C/sub 3/H/sub 6/O), ammonia (NH/sub 3/), hydrogen sulfide (H/sub 2/S) and water (H/sub 2/O). The method of study of the collisions was by time-of-flight analysis. Li* atoms traversed a 35-cm flight path usually occupied by a target gas before arriving at an excited-atom detector. Electric field ionization of the Li* atoms followed by detection of the resulting ions allowed for counting of individual atoms. Comparison of the time-of-flight spectra with and without a target gas present in the vacuum system allowed for a determination of the scatteirng cross sections for each target. With the atomic and nonpolar molecular targets, the cross sections were of order 10/sup -14/cm/sup 2/ and signal loss occurred by deflection of the Li* atoms from the beam. The deflection was observed directly in separate experiments. The observations are in agreement with predictions based on a model in which the Li/sup +/ core ion interactions with the target atom or molecule by inducing a dipole in the target.

• Research Organization: Oregon State Univ., Corvallis (USA)
• OSTI ID: 6265961
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ALKALI METALS
ALKANES
AMMONIA
ATOM COLLISIONS
ATOM-ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
ATOMIC BEAMS
BEAMS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
COLLISIONS
CORRECTIONS
CROSS SECTIONS
DATA
DEUTERIUM
DIPOLE MOMENTS
ELECTRON COLLISIONS
ELECTRON-ATOM COLLISIONS
ELEMENTS
EXPERIMENTAL DATA
FLUIDS
GASES
HYDRIDES
HYDROCARBONS
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
HYDROGEN SULFIDES
INFORMATION
IONIZATION
ISOTOPES
KRYPTON
LIGHT NUCLEI
LITHIUM
METALS
METHANE
MOLECULE COLLISIONS
MOMENTUM TRANSFER
NEON
NITROGEN
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
RARE GASES
RYDBERG CORRECTION
SCATTERING
STABLE ISOTOPES
SULFIDES
SULFUR COMPOUNDS
TIME-OF-FLIGHT METHOD
WATER