title: Water on the sun: line assignments based on variational calculations.
abstract: The infrared spectrum of hot water observed in a sunspot has been assigned. The high temperature of the sunspot (3200 K) gave rise to a highly congested pure rotational spectrum in the 10-micrometer region that involved energy levels at least halfway to dissociation. Traditional spectroscopy, based on perturbation theory, is inadequate for this problem. Instead, accurate variational solutions of the vibration-rotation Schrödinger equation were used to make assignments, revealing unexpected features, including rotational difference bands and fewer degeneracies than anticipated. These results indicate that a shift away from perturbation theory to first principles calculations is necessary in order to assign spectra of hot polyatomic molecules such as water.
authors.affiliation: Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: O L
authors.initials: OL
authors.lastname: Polyansky
authors.forename: N F
authors.initials: NF
authors.lastname: Zobov
authors.forename: S
authors.initials: S
authors.lastname: Viti
authors.forename: J
authors.initials: J
authors.lastname: Tennyson
authors.forename: P F
authors.initials: PF
authors.lastname: Bernath
authors.forename: L
authors.initials: L
authors.lastname: Wallace
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D019445:Solar Activity; D016082:Solar System; D013055:Spectrophotometry, Infrared; D013696:Temperature; D014867:Water / Q000032:analysis* / Q000737:chemistry
chemical_list: D014867:Water