Disorientation of 3He 1D States in 3He–3He Collisions

1974 ◽  
Vol 52 (17) ◽  
pp. 1615-1621 ◽  
Author(s):  
M. Pinard ◽  
J. Van Der Linde
Keyword(s):  
Angular Momentum ◽  
Cross Sections ◽  
Nuclear Spin ◽  
Ground State ◽  
Hyperfine Coupling ◽  
Optical Pumping ◽  
Excited Atom ◽  
Theoretical Treatment

Cross sections have been measured for the disorientation of the 3 1D, 4 1D, and 5 1D states of 3He in collisions with the ground state atoms. Oriented n1D state atoms are produced by exciting in a discharge 3He atoms whose nuclei have been oriented by optical pumping. The role of hyperfine coupling is investigated and the theoretical treatment of the effect of collisions on the orientation of the excited atom, which does not require instantaneous recoupling of the nuclear spin I and the electronic angular momentum J after each collision, is presented.

Notizen: Wirkungsquerschnitte für Gleichverteilung der 62P3/2-Zustände von Cäsium durch Stöße mit gesättigten Kohlenwasserstoffen

1969 ◽  
Vol 24 (6) ◽  
pp. 1030-1031
Author(s):  
N . Fronimos ◽  
J. Fricke ◽  
J. Haas
Keyword(s):  
Angular Momentum ◽  
Cross Sections ◽  
Selection Rule ◽  
Optical Pumping

Additional cross sections for collisionally induced mixing of the Cs-62P3/2 sublevels have been measured from optical pumping with σ+ D2-light. Using the model of a random re­orientation of the electronic angular momentum during the collision the derived cross sections are: Cs-CH4 (206±40) Å2, Cs-C2H6 (303±60) Å2, Cs-C3H8 (370 ±70) Å2. The existence of a selection rule mJ ﹘ /→ ﹘mJ would in­crease these values by a factor of 1.5.

QUASICLASSICAL TRAJECTORY STUDY OF PRODUCT POLARIZATIONS IN THE H(2S) + NH → N(4S) + H2 REACTION

2012 ◽  
Vol 11 (06) ◽  
pp. 1297-1310 ◽  
Author(s):  
LIN LI ◽  
SHUNLE DONG
Keyword(s):  
Angular Momentum ◽  
Cross Sections ◽  
Differential Cross ◽  
Ground State ◽  
Calculation Method ◽  
Collision Energy ◽  
Potential Surface ◽  
Angular Distributions ◽  
Title Reaction ◽  
Energy Dependent

Based on the DMBE potential surface of the 4 A ″ ground-state, the product rotational polarizations in the title reaction are studied by using quasiclassical trajectory (QCT) calculation method. Three angular distributions of P(θr), P(Φr), P(θr, Φr) and the four polarization-dependent differential cross sections (PDDCSs) were calculated for the collision energy range of 1–20 kcal/mol. The results revealed that the product is backward-scattering and the product rotational angular momentum j′ is aligned and oriented. With the increment of collision energy, the degree of the product alignment and orientation is enhanced, showing the collision energy-dependent behaviors of the product polarizations.

A QUASI-CLASSICAL TRAJECTORY STUDY ON STEREODYNAMICS OF THE F + HCl (v = 0, j = 0) → HF + Cl REACTION

2012 ◽  
Vol 11 (03) ◽  
pp. 663-674 ◽  
Author(s):  
XIAN-FANG YUE ◽  
PEI FENG
Keyword(s):  
Angular Momentum ◽  
Cross Sections ◽  
Ground State ◽  
Energy Surface ◽  
Center Of Mass ◽  
Classical Trajectory ◽  
Polar Coordinates ◽  
Angular Distributions ◽  
Title Reaction ◽  
Mass Frame

Quasiclassical trajectory (QCT) calculations for the title reaction are carried out by employing the recent developed accurate potential energy surface of the 12A′ ground state. Two angular distributions, P(θr) and P(ϕr), with θr, ϕr being the polar angles of the product angular momentum, and two commonly used polarization dependent differential cross sections, (2π/σ)(dσ00/dωt) and (2π/σ)(dσ20/dωt), with ωt being the polar coordinates of the product velocity, are generated in the center-of-mass frame. It was found that the product rotational angular momentum j′ is not only aligned, but also oriented along the negative direction of y-axis. We also investigated the product state distributions in the present work, and found that the vibrational and rotational state distributions are inverted. Influences of collision energies on the product polarization and state distributions are also shown and discussed.

scholarly journals Laser Assisted Collisions of Electrons with Metal Vapours

1996 ◽  
Vol 49 (2) ◽  
pp. 481 ◽  
Author(s):  
PJO Teubner ◽  
PM Farrell ◽  
V Karaganov ◽  
MR Law ◽  
V Suvorov
Keyword(s):  
Electron Scattering ◽  
Cross Sections ◽  
Ground State ◽  
Optical Pumping ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Kinematic Range ◽  
Excitation Process ◽  
Metal Vapour ◽  
Superelastic Scattering

Three separate experiments are described which use laser radiation to probe the details of electron scattering processes from metal vapour targets. Results from superelastic scattering experiments from calcium are presented. The experiments were carried out at incident energies of 25�7 and 45 eV referred to the ground state. Scattering amplitudes derived from these experiments demonstrate that current theories are inadequate. The coherence of the excitation process has been studied by measuring the total polarisation. It is shown that the excitation process is coherent over the whole kinematic range. Preliminary results from a study of superelastic electron scattering from lithium are discussed where it is shown that a quantum electrodynamical model can be used to describe the optical pumping process in 6Li and 7Li. In addition the first superelastic electron spectrum is presented for experiments on lithium. A stepwise excitation technique is described with which cross sections for the electron impact excitation of the 3d9 4s2 2D state in copper can be measured. The experiments are complicated by the presence of D states in the incident copper beam. The origin of these D states is described as is a modification of the technique which leads to their removal.

scholarly journals The Physical Origin of Fitting Laws for Rotational Energy Transfer

1986 ◽  
Vol 6 (1) ◽  
pp. 61-84 ◽  
Author(s):  
B. J. Whitaker ◽  
Ph. Brechignac
Keyword(s):  
Angular Momentum ◽  
Cross Sections ◽  
Energy Surface ◽  
Rotational Energy ◽  
Physical Models ◽  
Intermolecular Potential ◽  
Historical Overview ◽  
Physical Origin ◽  
Rotational Energy Transfer

An historical overview of the various parameterised forms describing RET processes (fitting laws) is presented. The physical models behind these "laws" are compared. Particular attention is paid to the role of angular momentum constraints and to the energy dependence of the state-to-state cross-sections. Finally it is shown how general trends can be inferred from the topology of the intermolecular potential energy surface.

The role of the nuclear spin in optical pumping withD 2-light

1972 ◽  
Vol 255 (1) ◽  
pp. 14-24 ◽  
Author(s):  
M. Elbel ◽  
A. Koch ◽  
W. Schneider
Keyword(s):  
Nuclear Spin ◽  
Optical Pumping
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