Stimulated photon echo for angular analysis of elastic and depolarizing Yb/sup /--noble-gas collisions

Journal Article · Sun Sep 01 00:00:00 EDT 1985 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.32.1624· OSTI ID:5430813

Keller, J C; Le Gouet, J L

Elastic and depolarizing collisions between excited ytterbium atoms (6s6p /sup 3/P/sub 1/ level) and noble gases (He, Ne, and Xe) are investigated using a stimulated-photon-echo technique. The method is sensitive to collisional velocity changes concerning both the total population rho/sup 0/ and the alignment rho/sup 2/ of the level. More specifically, it enables us to compare precisely the velocity changes associated with elastic scattering and with alignment-preserving scattering. This represents an improvement with regard to previous works. A detailed theoretical discussion of depolarizing collisions in laser spectroscopy is presented. A simplified density-matrix equation is derived under appropriate approximations. Stimulated photon-echo data for elastic scattering are interpreted within the limits of small-angle scattering in a long-range van der Waals potential; total elastic scattering cross sections are derived from comparison between experiment and calculation: sigma/sub He//sup el/ = 220(20) A/sup 2/, sigma/sub Ne//sup el/ = 320(20) A/sup 2/, sigma/sub Xe//sup el/ = 1240(60) A/sup 2/. Total rates for destruction of alignment are measured in an auxiliary standard photon-echo experiment; the corresponding cross sections are sigma/sub He//sup(/sup 2/) = 94(3) A/sup 2/, sigma/sub Ne//sup(/sup 2/) = 123(7) A/sup 2/, sigma/sub Xe//sup(/sup 2/) = 300(20) A/sup 2/. Stimulated photon-echo data for depolarizing collisions are successfully compared with a calculation that we develop starting from a long-range anisotropic model potential.

• Research Organization: Laboratoire Aime Cotton, Centre National de la Recherche Scientifique II, Btiment 505, 91405 Orsay Cedex, France
• OSTI ID: 5430813
• Journal Information: Phys. Rev. A; (United States), Vol. 32:3
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
HELIUM
ATOM-ATOM COLLISIONS
NEON
XENON
YTTERBIUM
DENSITY MATRIX
DEPOLARIZATION
DIFFERENTIAL CROSS SECTIONS
ELASTIC SCATTERING
ENERGY SPECTRA
EXCITED STATES
SCATTERING AMPLITUDES
AMPLITUDES
ATOM COLLISIONS
COLLISIONS
CROSS SECTIONS
ELEMENTS
ENERGY LEVELS
FLUIDS
GASES
MATRICES
METALS
NONMETALS
RARE EARTHS
RARE GASES
SCATTERING
SPECTRA
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena