Interstellar and cometary ices are thought to have migrated to Earth and been involved in the birth of primordial biological molecules here. The ESA Rosetta mission sent a spacecraft to explore the icy comet 67P/Churyumov-Gerasimenko to find answers regarding the mystery of the origins of life on Earth and ammonium cyanide - NH4CN – and other salts were detected. It is possible that these ammonium salts may be the parent species that produce the NH3 and HCN gas observed in cometary comae, but further studies are required. NH4CN can be formed by the acid-base reactions of HCN and NH3 under the low-temperature conditions of dense interstellar clouds, and NH3 has been detected in interstellar ice, while HCN has been detected in the gas phase. Thus, NH4CN or similar ammonium-based salts may be present in interstellar ices and could possibly be the source of this material in comets or other planetary bodies. We have studied several physical properties of NH4CN at low temperatures (120 – 165 K), including its visible refractive index, mass density, sublimation rates, and desorption energy. Moreover, using FTIR transmission spectroscopy in the near- and mid-infrared, we have also determined the band strengths of NH4+ and CN- IR absorption features and the IR optical constants (n & k) at wavelengths from 2 to 20 μm (5000 to 500 cm-1). Films of pure NH4CN were prepared at 125 K by the co-deposition of HCN with an excess of NH3 onto an optically-flat, gold-mirror electrode, which is located on the surface of a quartz-crystal microbalance (QCM). The refractive index and density were determined with a double-laser interferometer system. The sample was cooled to 120 K then warmed to 165 K at a constant heating rate (1 K min-1) to determine the sublimation rate at each temperature, which allowed us to also determine the NH4CN desorpution energy. IR band strengths and optical constants were determined by transmission spectroscopy of a film prepared on an IR-transparent substrate.

Experimental study of NH4CN at low temperatures: IR optical properties and sublimation behavior

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.