Vacuum-UV absorption spectroscopy of interstellar ice analogues. iii. isotopic effects

G. A. Cruz-Diaz, G. M. Muñoz Caro, Y. J. Chen

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

This paper reports the first measurements of solid-phase vacuum-ultraviolet (VUV) absorption cross-sections of heavy isotopologues present in icy dust grain mantles of dense interstellar clouds and cold circumstellar environments. Pure ices composed of D2O, CD3OD, 13CO2, and 15N15N were deposited at 8 K, a value similar to the coldest dust temperatures in space. The column density of the ice samples was measured in situ by infrared spectroscopy in transmittance. VUV spectra of the ice samples were collected in the 120-160 nm (10.33-7.74 eV) range using a commercial microwave discharged hydrogen flow lamp as the VUV source. Prior to this work, we have recently submitted a similar study of the light isotopologues (Cruz-Diaz, Mu~noz Caro & Chen). The VUV spectra are compared to those of the light isotopologues in the solid phase, and to the gas phase spectra of the same molecules. Our study is expected to improve very significantly the models that estimate the VUV absorption of ice mantles in space, which have often used the available gas phase data as an approximation of the absorption cross sections of the molecular ice components. We will show that this work has also important implications for the estimation of the photodesorption rates per absorbed photon in the ice.

Original languageEnglish
Pages (from-to)2370-2376
Number of pages7
JournalMonthly Notices of the Royal Astronomical Society
Volume439
Issue number3
DOIs
StatePublished - Apr 2014

Keywords

  • Abundances-ISM
  • Astrochemistry-molecular data-molecular processes-ISM
  • ISM
  • Molecules-ultraviolet

Fingerprint

Dive into the research topics of 'Vacuum-UV absorption spectroscopy of interstellar ice analogues. iii. isotopic effects'. Together they form a unique fingerprint.

Cite this