Collisional processes involving the metastable 6s5d [sup 3]D[sub J] levels of barium

Miscellaneous · Fri Jan 01 00:00:00 EST 1993

OSTI ID:7003901

Ehrlacher, E A

The authors have studied a number of collisional processes involving the metastable 6s5d [sup 3]D[sub J] levels of barium. The metastable levels were populated through optical pumping of the 6s[sup 2] [sup 1]S[sub 0] [yields] 6s6p [sup 3]P[sup 0][sub 1] intercombination transition at 791.13 nm, followed by either spontaneous or stimulated decay into the [sup 3]D[sub 1,2] levels. Collisional mixing further redistributed population over the three [sup 3]D[sub J] levels. The authors measured line shapes and foreign-gas broadening rates for the 6s5d [sup 3]D[sub 1] [yields] 5d6p [sup 1]D[sup 0][sub 2], 6s5d [sup 3]D[sub 2] [yields] 5d6p [sup 3]F[sub 3], and 6s5d [sup 3]D[sub 3] [yields] 5d6p [sup 3]F[sub 4] transitions by using a cw pump laser to populate the metastable levels and monitoring the absorption of a weak cw probe laser. In additions, line shapes and broadening rates were also measured for the 6s[sup 2] [sup 1]S[sub 0] [yields] 6s6p [sup 1]P[sup 0][sub 1] resonance and 6s[sup 2] [sup 1]S[sub 0] [yields] 6s6p [sup 3]P[sup 0][sub 1] intercombination transitions. Using the broadening rate coefficients determined for these transitions, they were able to accurately estimate the total number density of barium atoms in the heat-pipe oven, as well as the number density of atoms in the metastable levels when optically pumping the vapor. The authors estimate that 60% of the barium atoms were pumped into the metastable levels using 200 mW of cw laser power. They have also developed a useful technique for studying time-resolved line shapes that combines the time resolution capabilities of a pulsed laser with the frequency resolution of a narrowband, single-mode cw laser. With this technique, they have measured time-dependent line shapes for transitions involving metastable levels using a pulsed pump laser and a cw probe. A comparison of the pulsed and cw line shapes indicates that experimental conditions are below the threshold where Stark broadening is significant.

• Research Organization: Lehigh Univ., Bethlehem, PA (United States)
• OSTI ID: 7003901
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
BARIUM
COLLISIONS
METASTABLE STATES
ARGON
ATOM-ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
ENERGY-LEVEL TRANSITIONS
NITROGEN
ALKALINE EARTH METALS
ATOM COLLISIONS
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FLUIDS
GASES
METALS
MOLECULE COLLISIONS
NONMETALS
RARE GASES
664300* - Atomic & Molecular Physics- Collision Phenomena- (1992-)