Buffer gas cooled ice chemistry. II. Ice generation and mm-wave detection of molecules desorbed from an ice

T J Hager; B M Moore; Q D Borengasser; A C Kanaherarachchi; K T Renshaw; S Radhakrishnan; G E Hall; B M Broderick

doi:10.1063/5.0225903

Buffer gas cooled ice chemistry. II. Ice generation and mm-wave detection of molecules desorbed from an ice

J Chem Phys. 2024 Sep 7;161(9):094201. doi: 10.1063/5.0225903.

Authors

T J Hager¹, B M Moore¹, Q D Borengasser¹, A C Kanaherarachchi¹, K T Renshaw¹, S Radhakrishnan¹, G E Hall², B M Broderick¹

Affiliations

¹ Department of Chemistry, University of Missouri, Columbia, Missouri 65203, USA.
² Brookhaven National Laboratory, Chemistry Division, Upton, New York 11973, USA.

PMID: 39225516
DOI: 10.1063/5.0225903

Abstract

This second paper in a series of two describes the chirped-pulse ice apparatus that permits the detection of buffer gas cooled molecules desorbed from an energetically processed ice using broadband mm-wave rotational spectroscopy. Here, we detail the lower ice stage developed to generate ices at 4 K, which can then undergo energetic processing via UV/VUV photons or high-energy electrons and which ultimately enter the gas phase via temperature-programmed desorption (TPD). Over the course of TPD, the lower ice stage is interfaced with a buffer gas cooling cell that allows for sensitive detection via chirped-pulse rotational spectroscopy in the 60-90 GHz regime. In addition to a detailed description of the ice component of this apparatus, we show proof-of-principle experiments demonstrating the detection of H2CO products formed through irradiation of neat methanol ices or 1:1 CO + CH4 mixed ices.