Magnetic deflection spectrum of VCl4

A. Gedanken, N. A. Kuebler, M. B. Robin, D. R. Herrick

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


The magnetic deflection spectra of VCl4 seeded into supersonic beams of the rare gases have been determined. It is found that in the heavier rare gases (Ar, Kr, and Xe) the Stern-Gerlach splitting patterns are just those expected for a molecule in a spin-doublet state, as complicated by the presence of nondeflecting (VC14)X clusters. In these beams, the satellite splittings of unclustered VC14 scale with the square of the beam velocities, and there is no evidence in the Stern-Gerlach spectra for the rapid (10−9 s) intramolecular spin relaxation (ISR) so apparent in the EPR and NMR spectra of this molecule in condensed phases. Modeling of the ISR effect on SG deflection spectra and comparison of these results with experiment shows that if ISR is in any way active in beam-cooled VC14, the spin relaxation time is longer than 10−4 s. By contrast, the deflection spectrum of VC14 seeded into He is far more compressed than otherwise expected, suggesting that ISR may be at work in this case. Analysis of the observed Stern-Gerlach band shape of VC14 in the He beam shows that if ISR is the cause of the anomalous spectrum, then the ISR time is approximately 10−6 s. The use of magnetic deflection to determine the possible association of the carrier gases with the paramagnetic target molecule is presented as an illustration of neutral-molecule mass spectrometry.

Original languageEnglish
Pages (from-to)5568-5572
Number of pages5
JournalJournal of the American Chemical Society
Issue number15
StatePublished - 1 Jul 1989


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