Heinrich Winter

Measurement of metastable fractions in multiply charged ion beams by ion excitation in core-conserving electron capture

Conservation of the electronic configuration of ground-state and metastable ions in the capture of an electron from Li(2s) into excited states has been utilised to measure metastable ion beam fractions for multiply charged ions. Results are presented for beams of C2+, N2+, N3+ and O4+ respectively, which have been produced by means of an ECR ion source.

2-ELECTRON AND MORE-ELECTRON TRANSITIONS IN SLOW MULTICHARGED ION-HE COLLISIONS

Abstract Cross sections for double-electron capture into bound states and for simultaneous single-electron capture and target ion excitation have been measured for impact of slow (0.5–6 keV/amu) multicharged ions C 4+ , N 4+ , N 5+ , O 5+ on He. Results are discussed in connection with a recent extended classical over-barrier model for multiple-electron capture, and by consideration of relevant quasimolecular potential energy curve crossings.

What motivates men to offer sperm donation via the internet

Abstract To investigate why men offer sperm donation via the internet, a questionnaire was disseminated via 39 Dutch-language websites thought to be visited by potential sperm donors. Nine internet donors completed the survey, men who typically knew the women they were donating to. Their responses were compared with those of a control group of 35 general sperm bank donors who were recruited using flyers in Dutch sperm banks, and who were typically unaware of the identity of the eventual recipients. The findings shed light on the motives and attitudes of internet donors. Both groups of donors indicated that their primary motivation for donating was altruism (>80% of all respondents). However, internet donors had a more pronounced desire to procreate than sperm bank donors (6 out of 9, i.e. 66 vs. 22%, respectively) and more often felt that they had good genes they wished to pass on (5 out of 9, i.e. 55 vs. 31%, respectively). The main reason internet donors gave for donating via the internet was that they wanted to know the prospective parents and be kept up to date on the progress of the offspring conceived from their donations. This distinguishes them significantly from sperm bank donors. A further finding was that they were not prompted to avoid the formal donation circuit for which, by law in the Netherlands, pregnancies resulting from donations have to be registered in a central database. This study is subject to several, in some cases inevitable, limitations, but it provides an interesting starting point that future studies can seek to confirm and extend.

SINGLE-ELECTRON CAPTURE INTO C-3+(N, L) SUBSHELLS IN C-4+-LI COLLISIONS (20-80 KEV)

Absolute emission cross sections have been measured for 29 lines of the C IV spectrum in the wavelength range 20-500 nm resulting from C4+-Li collisions at impact energies between 0.83 and 6.67 keV amu-1. From these emission cross sections one-electron capture cross sections sigma nl have been deduced for all subshells with n<or=7, using known transition probabilities. It is found that electron capture takes dominantly into the n=5 shell, as expected from a classical model. Capture into the n=6,7 shells increases with increasing impact energy, whereas capture into the n=5 shell decreases slightly, resulting in a total capture cross section of about 2*10-14 cm2 which is almost independent of energy. The distributions over l subshells within each n shell are strongly energy dependent, shifting to larger values of l with increasing energy. However, capture into the 5g subshell is dominant over the whole energy range. The results are partly explained qualitatively and are in good agreement with very recent calculations by Fritsch and Lin (1983) who used a modified two-centre atomic orbital expansion.

SUBSHELL-SELECTIVE ELECTRON-CAPTURE FROM LITHIUM BY SLOW MULTIPLY CHARGED IONS

Absolute cross sections for (n, l) subshell-selective electron capture in C4+-Li(2s) collisions at ion impact energies of 20–80 keV have been measured and compared with corresponding recent calculations. It is also shown that for capture from Li(2s) by various Be-like (C2+, N3+, C4+) and B-like (N2+) multiply charged ions the electronic configurations of the primary ions remain practically unchanged (“core conservation”). The latter feature could be utilized to measure the metastable fractions of beams of these ions. Finally, it is demonstrated in which way the subshell-selective capture from Li atoms can serve for detailed information on impurity transport in magnetically confined plasmas.

CRYSTAL-STRUCTURE OF THE NOVEL COMPOUND (1-ALPHA, 3-BETA, 5-ALPHA)-1,3-DIPHENYL-5-HYDRIDO-5-ISOPROPOXY-1-LAMBDA-6,3-LAMBDA-6,2,4,6,5-LAMBDA-5-DITHIATRIAZAPHOSPHORINE-1,3-DIOXIDE - A COMPARISON WITH RELATED STRUCTURES

Abstract The title compound (1α, 3β, 5α)-(NSOPh)2NP(H)O-i-Pr crystallizes in the spacegroup P21/n with cell dimensions: a = 12. 150(2), b = 8.911(1), c = 17.614(3) A, β = 107.52(1)o; Z = 4. The structure was solved by direct methods and refined by least-squares techniques to an R value of 0.048 for 2420 independent reflections (collected at room temperature) with I > 2.5 σ(I). The unit cell contains dimeric units which are formed by unprecedented P[sbnd]H…O[dbnd]S bridges. The conformation of the inorganic ring skeleton can be described as a boat; phosphorus and sulfur atoms show a distorted tetrahedral geometry. The S[sbnd]N bond lengths differ slightly, ranging from 1.547(3) to 1.588(2) A. The exocyclic bond lengths are P[sbnd]H = 1.34(2), P[sbnd]O = 1.553(2), S[sbnd]O = 1.439(2) (mean value), and S[sbnd]C = 1.767(4) (mean value) A. From a comparison with analogous structures the degree of asymmetry (ΔI = {[P[sbnd]N]-[S[sbnd]N]}A) in the SNP unit is related to the difference in electronegativity between...

DERIVATIVES OF NPCL2(NSOCL)2 AND (NPCL2)2NSOCL .23. REACTIVITY IN AMINOLYSIS REACTIONS BY NH3

Reactions of the cyclic systems (NPCl2)2NSOX and NPCl2(NSOX)2 (X = F, Cl, Ph) with NH3 in diethyl ether or acetonitrile at low temperature provide convincing evidence that the P-bonded chlorine atoms are replaced by NH2 groups along a geminal pathway. No disruption of the S-F and S-Ph bonds occurs. Aminolysis of NPCl2(NSOCl)2 proceeds to NP(NH2)2(NSOCl)2, followed by decomposition, (NPCl2)2NSOCl can be transformed to NPClNH2NP(NH2)2NSOCl without cleavage of the ring skeleton

Methoden en technieken voor de juridische wetenschap

Boekbespreking van Frans L. Leeuw and Hans Schmeets, Empirical Legal Research. A Guidance Book for Lawyers, Legislators and Regulators, Cheltenham, Edward Elgar Publishing, 2016, 328 pagina’s

STATE-SELECTIVE SINGLE-ELECTRON CAPTURE BY 80-KEV C-4+ IONS FROM HE, H-2 AND LI

Absolute excitation cross sections for single-electron capture into selected n, l states have been determined by VUV spectroscopy for impact of 80 keV C4+ on He, H2 and Li. For all three collision systems the predominant final ion states belong to one or two electronic shells only. Within such shells a preferential population of higher l sublevels is found.