Shift and broadening of resolved hydrogen Balmer-. cap alpha. fine-structure lines in helium

Journal Article · Sat Dec 01 04:00:00 EST 1979 · Phys. Rev., A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.20.2278· OSTI ID:5857344

Weber, E W

Accurate values for the density shift and broadening of five isolated H/sub ..cap alpha../ fine-structure transitions have been measured. Doppler-free polarization and double-quantum saturation spectroscopy with a cw dye laser are used in a He dc discharge with 1% H/sub 2/. The negative shifts and the huge broadening values are correctly predicted by an impact-approximation theory taking into account the large cross sections for fine-structure transfer (quenching) collisions and only Van der Waals interaction between H* and He. Consequences of a comparison with the positive shift of the unresolved H/sub ..cap alpha../ line and of the alkali-metal D lines in He buffer gas are discussed. For pressures below 0.1 Torr hfs decoupling collisions give rise to a positive shift of single H/sub ..cap alpha../ fine-structure lines and to a collisional narrowing effect analogous to that observed in nuclear magnetic resonance.

• Research Organization: Department of Physics, Stanford University, Stanford, California 94305
• OSTI ID: 5857344
• Journal Information: Phys. Rev., A; (United States), Journal Name: Phys. Rev., A; (United States) Vol. 20:6; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
640304 -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
BALMER LINES
COLLISIONS
CRYOGENIC FLUIDS
ELEMENTS
ENERGY-LEVEL TRANSITIONS
FINE STRUCTURE
FLUIDS
HELIUM
HYDROGEN
LINE BROADENING
MOLECULE COLLISIONS
NONMETALS
RARE GASES
SPECTRAL SHIFT