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Determination of dissociation temperature for ArO(+) in inductively coupled plasma-mass spectrometry: Effects of excited electronic states and dissociation pathways

TitleDetermination of dissociation temperature for ArO(+) in inductively coupled plasma-mass spectrometry: Effects of excited electronic states and dissociation pathways
Publication TypeJournal Article
Year of Publication2011
AuthorsMcIntyre SM, Ferguson JW, Houk RS
Journal TitleSpectrochimica Acta Part B-Atomic Spectroscopy
Volume66
Pages581-587
Date Published08
Type of ArticleArticle
ISBN Number0584-8547
Accession NumberWOS:000295745600002
KeywordsArgon oxide ion: ArO(+), extraction, gas-dynamics, high-resolution, Inductively coupled, Inductively coupled plasma-mass spectrometry, interface, interferences, Ion extraction, origins, part i, partition-functions, PLASMA, polyatomic ions, skimmer
Abstract

The method of comparing experimental and calculated ion ratios to determine a gas kinetic temperature (T(gas)) characteristic of the origin of a polyatomic ion in inductively coupled plasma-mass spectrometry (ICP-MS) is applied to ArO(+). Repeated measurements of ion ratios involving this species yield erratic T(gas) values. Complications arise from the predicted presence of a low-lying excited electronic state ((2)Pi) above the (4)Sigma ground state. Omission of this excited state yields unreasonably high temperatures (> 10,000 K) for nine out of nineteen trials. Inclusion of the excited electronic state in the partition function of ArO(+) causes temperatures to increase further. The problem appears to be related to the prediction that ArO(+) in the (2)Pi excited state dissociates into Ar(+) and O, different products than ArO(+) (4)Sigma which dissociates into Ar and O(+). Adjustments to the calculations to account for these different products yield reasonable temperatures (2100 to 3500 K) that are consistent from day-to-day and similar to those seen for other weakly-bound polyatomic ions. (C) 2011 Elsevier B.V. All rights reserved.
DOI10.1016/j.sab.2011.06.002
Alternate JournalSpectroc. Acta Pt. B-Atom. Spectr.