We report measurements of differential cross sections of rotationally (Δj = 15 to 79)–vibrationally (Δv = 1) inelastic collisions in ground electronic state Na2 with Ar on a level to level basis. The experiment is performed using crossed supersonic molecular beams and two dye lasers, one for tagging the initial level (v = 0, ji = 7), and the second for detection of the final level (v = 1, jf = 7+Δj) and scattering angle ϑ. A description of the experimental apparatus and technique is given. The differential cross sections all exhibit a pronounced rise at some minimum angle to a maximum followed by a gradual decline out to ϑ = π. The angular positions of the rise and peak increase nearly linearly with Δj. The Δv = 1, Δj integral cross sections are roughly constant in size even though the inelasticity (ΔE) varies over a large fraction of the available initial kinetic energy (∼2400 cm−1); by comparison, the Δv = 0, Δj integral cross sections, over a similar range in Δj, follow a power law dependence in ΔE. The qualitative features of both the differential and integral cross sections appear consistent within the framework of a classical, sudden collision on a sharply repulsive potential.
By means of collinear laser spectroscopy at ion beams of Ar +, S + and CI + the isotope shifts of a total of twelve lines could be measured. All the lines are of the type 3p "--~ 3d-~3p"-~4p (3p" being the proper ground configuration of the ions). All the measured shifts are unusually large and prevailingly due to a strong specific mass effect or momentum correlation of the 3d electron with the inner p-shells. The measured shifts could be quantitatively reproduced by computation of the inherent Vinti integrals.
We have operated an electrooptical modulator to generate sidebands to the laser used for optical pumping of a helium-3 gas. Spreading the laser power over the Doppler absorption profile of the metastable helium atoms can enhance the efficiency of the optical pumping process. This improvement is discussed in terms of velocity changing collisions and compared to the result of a velocity selective optical pumping experiment
The transfer of magnetic polarization from state 3p 21"1/2 to state 3p 2P3/2 in sensitizing collisions of sodium atoms with noble gas atoms has been observed. Sodium atoms were excited by absorption of D 1 a+-quanta. When buffer gas was added to the sodium vapour, unequal amounts of D2 a+ and Daaquanta could be detected in the fluorescent light. The difference of the amounts turned out to be proportional to the polarization transferred. The measurement of this difference as a function of the buffer gas pressure provided a method of determining the cross-sections of the polarization transfer. Values of the cross-sections are 22, 24, 26, 20, 23 A. 2 for the buffer gases He, Ne, Ar, Kr, Xe, respectively. A preliminary investigation shows that the sign of the polarization transferred is reversed when the vapour is exposed to a strong magnetic field acting along the incident light beam.
Mit, 3 AbbildungenInhaltsubersicht Es wird eine theoretische Deutung der Hyperfeinstrukturaufspaltringsfaktoren (A-Faktoren) gegeben, die in verschiedenen Arbeiten an den Termeii der Konfiguration 3d 4s 4p des Scandium I-Spektrums, der Konfiguration 4d 5s 5y des Yttrium I-Spektrums und der Konfiguration 3d9 4s 4p des Kupfer I-Spektrums gemessen wurden. Um von moglichst genauen Elektroneneigenfunktionen ausgehen zu konnen, wird zunachst die Feinstruktur der drei genannten Spektren diskutiert. Mit Hilfe so gewonnener Eigenfunktionen werden Dreielektronenmatrixelemente der magnetisehen Hyperfeinstrukturwechselwirkung aufgestellt und unter Anwendung der bekannten Formeln von G ii t t i 11 g e r urid P a u l i reduziert. Die hierbei auftretenden reduzierten Matrixelemente aL sind nur noch einelektronenabhangig. Sie werden im Fall der drei vorgenannten Spektren aus den MeBdaten bestimmt und Kernmomente aus ihnen hergeleitet. Die so bestimmteii Kernmomente stimmen mit den genauen Kerninduktionswerteri befriedigend iiberein. Quadrupolwechselwirkung wurde bisher nicht beriicksichtigt, da hierzu keine MeBdaten vorliegen.
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