Level-crossing measurements on the excitation of 1snd<sup>1</sup>D levels of He I in He<sup>+</sup>-He collisions

Müller, Robert; Oppen, Gebhard von; Perschmann, W. D.; Schilling, W.

doi:10.1088/0022-3700/15/18/014

Cited by 6 publications

(8 citation statements)

References 14 publications

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“…The relative excitation cross sections dx of the 41D level measured in this work for the collision systems H~ (Df)-He and He-He can be compared with those measured earlier for He + impact excitation [12]. Results almost equal to the He + data were obtained for Ne + excitation by M. Anton et al [13], In the final part of this Sect.…”

Section: Discussion Of the Excitation Processsupporting

confidence: 65%

“…So far, these techniques have been used to investigate ion-impact excitation of 1 s nd states of HeI [11][12][13]. Considering 1D levels and angle-integrated excitation matrices, only state multipoles o-~ with k =0,2 and 4 and # = 0 can be non-zero if the quantization axis refers to the direction of the ion beam.…”

Section: Introductionmentioning

confidence: 99%

“…Here o-D=%+2cq +2a 2 is the total excitation cross section. The results can be compared with excitation cross sections of the 41D substates obtained for He + -He [12] and Ne + -He collisions [13], where the ion velocity has been varied within a comparable range. While the polarization fraction P = (III -l-L)/( IIt + li) of the )~(41D -21 p) = 492 nm deduced from these experiments was found to vary only little with energy, the splitting of the magnetic depolarization signals revealed a remarkable energy dependence of the excitation process of the 41D level.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of impact-excited HeI states by applying magnetic and electric depolarization techniques

Aynacioglu

Meissner

Walachowicz

et al. 1991

Z Phys D - Atoms, Molecules and Clusters

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Abstract. The magnetic depolarization of the impact radiation at 2(41D-2tP)=492nm and 2(31D-2~P) = 668 nm as well as the splitting of the magnetic depolarisation signals in electric fields were investigated for t0-25 keV H~-(D~-)-He collisions (only 492 nm line) and for 5-22.5 keV He-He collisions (both lines). The results are compared with analogous measurements for He + -He and Ne + -He collisions and the dynamics of the excitation process are qualitatively discussed. In particular, we emphasize the importance of inertia for the evolution of the electron cloud during the final phase of the collision process.

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Section: Discussion Of the Excitation Processsupporting

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Analysis of impact-excited HeI states by applying magnetic and electric depolarization techniques

Aynacioglu

Meissner

Walachowicz

et al. 1991

Z Phys D - Atoms, Molecules and Clusters

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“…In two papers published recently [4,5] we reported the complete determination of excitation matrices of lsndtD2 levels of HeI by levelcrossing techniques. Here we are concerned with impact excitation of lsnd3D levels of He I by 35 keV He + -He collisions.…”

Section: Introductionmentioning

confidence: 99%

Analysis of level-crossing signals after impact excitation of 1snd 3 D levels of He I by He+-He collision

1984

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Level-crossing signals of impact radiation of He I have been analyzed with regard to the determination of excitation matrices. The signals have been registered at various electricfield strengths by sweeping a magnetic field strength ~ through the positions of Am =2 crossings of Zeeman substates of n3D2 and n3D3 levels (n=4 and 5) of He I excited by 35 keV-He § collisions. We analyzed the signal amplitudes and signal shapes with regard to a spin-dependence of the excitation matrix usually discarded by theoretical arguments. To this end a parametrization of spin-dependent excitation matrices has been performed, and the dependence of the level-crossing amplitudes on the 19 parameters obtained have been studied. It turned out that the observed relative signal amplitudes can satisfactorily be explained by only two parameters, the two multipole components of order k=2 and k--4 of the alignment of the orbital angular momentum. Thus in agreement with theoretical estimations no spin-dependence must be taken into account.

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“…3 It has to be kept in mind that the fluorescence radiation from direct excitation could not be separated from the fluorescence due to charge transfer excitation of the projectile, see [28] So, summing up, the situation seems to be rather contradictory to a quasimolecular approach for the description of impact excitation processes at the projectile velocities under consideration.…”

Section: Resultsmentioning

confidence: 99%

Excitation of He—41 D-substates by He+- and Ne+-projectiles investigated by level-crossing techniques

Anton

Schartner

Hasselkamp

et al. 1991

Z Phys D - Atoms, Molecules and Clusters

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Abstract. Collisions of He +-and Ne+-projectiles withHe at impact energies between 90 keV and 800 keV were investigated. Relative excitation cross sections for magnetic sublevels of He-41D were determined using levelcrossing techniques. Absolute excitation cross sections o,, of the Zeeman-sublevels are given using He-4 ~D cross sections from earlier measurements. The results show strong variations of the cross sections ao and a+ 1 with a quasi-oscillatory behaviour, a + 2 is much smaller than ao and a_+~.

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Level-crossing measurements on the excitation of 1snd¹D levels of He I in He⁺-He collisions

Cited by 6 publications

References 14 publications

Analysis of impact-excited HeI states by applying magnetic and electric depolarization techniques

Analysis of impact-excited HeI states by applying magnetic and electric depolarization techniques

Analysis of level-crossing signals after impact excitation of 1snd 3 D levels of He I by He+-He collision

Excitation of He—41 D-substates by He+- and Ne+-projectiles investigated by level-crossing techniques

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Level-crossing measurements on the excitation of 1snd1D levels of He I in He+-He collisions

Cited by 6 publications

References 14 publications

Analysis of impact-excited HeI states by applying magnetic and electric depolarization techniques

Analysis of impact-excited HeI states by applying magnetic and electric depolarization techniques

Analysis of level-crossing signals after impact excitation of 1snd 3 D levels of He I by He+-He collision

Excitation of He—41 D-substates by He+- and Ne+-projectiles investigated by level-crossing techniques

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Level-crossing measurements on the excitation of 1snd¹D levels of He I in He⁺-He collisions