The ground state of KO revisited: The millimeter and submillimeter spectrum of potassium oxide

Mark A. Burton, Benjamin T. Russ, Matthew P. Bucchino, Phillip M. Sheridan, Lucy M. Ziurys

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The millimeter/sub-millimeter spectrum of the KO radical has been recorded in the frequency range 90-534 GHz using direct absorption methods. The radical was synthesized by reacting potassium vapor, produced with a Broida-type oven, with either N2O or O2 mixed in argon carrier gas. Twenty-seven rotational transitions of KO were measured, each exhibiting a doublet structure with a relatively small splitting (∼100-200 MHz) that increased noticeably with frequency. A perturbation was apparent in the rotational lines at energies above ∼120 cm-1, which was more prominent in one doublet component. The data were successfully fit with a Hund's case (c) Hamiltonian, assuming that spectra arise from a 2Πi state, and rotational and effective lambda-doubling constants were determined. Higher order centrifugal distortion terms were needed to account for the perturbation. The spectra could also be fit as a 2Σ+ ground state, but less successfully, and the resulting rotational constant of B = 8235.4 MHz disagreed significantly with that predicted by theory. On the basis of the experimental data, the ground electronic state of KO has been assigned as 2Πi, although the 2Σ+ assignment cannot be entirely ruled out.

Original languageEnglish (US)
Pages (from-to)21960-21965
Number of pages6
JournalPhysical Chemistry Chemical Physics
Issue number39
StatePublished - 2019

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry


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