Infrared free electron laser induced photodesorption of CO and N₂ from solid amorphous water at cryogenic temperatures
Abstract
Photon induced processing of molecular ices is known to be important in a number of astrophysical environments. However, to date, astrophysical models tend to only incorporate ultra-violet induced photoprocesses. This is despite the fact that the flux of infrared (IR) photons is comparable to, and sometimes exceeds that of, ultra-violet photons in a number of environments. In order to determine whether IR photoprocesses are important under astrophysical conditions, we have undertaken experiments to investigate the IR-induced desorption of CO and N₂ from CO:H2O and N₂:H₂O mixed ices grown at 9 K. These studies were performed at FELIX, the free electron laser facility at Radboud University, Nijmegen, The Netherlands. Irradiation of the ices was performed in the mid-IR range from 2.9–12 µm and shows that photon induced desorption (PID) of CO and N₂ only occurs when the ices are irradiated at wavelengths that excite the vibrational modes of the H₂O ice. No PID is observed when the internal stretching modes of the dopant molecules are excited. The observed PID traces, recorded during the irradiation with a mass spectrometer, can be fitted with a bi-exponential decay function that shows the presence of a fast and a slow photodesorption process. These can be assigned to direct and indirect substrate-mediated resonant photodesorption processes. Power dependence studies show saturation and suggest that a complex process is leading to the observed PID. The data reported here clearly show that IR-driven photodesorption should be considered in astrophysical models.
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BibTeX
@article{jones2026infrared,
title = {{Infrared free electron laser induced photodesorption of CO and N₂ from solid amorphous water at cryogenic temperatures}},
author = {Kerry Jones and Jack Fulker and Domantas Laurinavicius and Ali Ozel and Johanna. Schrauwen and Britta Redlich and Jennifer A. Noble and Sergio Ioppolo and Martin Mccoustra and Wendy Brown},
journal = {Physical Chemistry Chemical Physics},
year = {2026},
month = nov,
doi = {10.1039/d5cp04525h},
url = {https://hal.science/hal-05850706v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Infrared free electron laser induced photodesorption of CO and N₂ from solid amorphous water at cryogenic temperatures
AU - Kerry Jones
AU - Jack Fulker
AU - Domantas Laurinavicius
AU - Ali Ozel
AU - Johanna. Schrauwen
AU - Britta Redlich
AU - Jennifer A. Noble
AU - Sergio Ioppolo
AU - Martin Mccoustra
AU - Wendy Brown
PY - 2026
DA - 2026/11/03
JO - Physical Chemistry Chemical Physics
DO - 10.1039/d5cp04525h
UR - https://hal.science/hal-05850706v1
AB - Photon induced processing of molecular ices is known to be important in a number of astrophysical environments. However, to date, astrophysical models tend to only incorporate ultra-violet induced photoprocesses. This is despite the fact that the flux of infrared (IR) photons is comparable to, and sometimes exceeds that of, ultra-violet photons in a number of environments. In order to determine whether IR photoprocesses are important under astrophysical conditions, we have undertaken experiments to investigate the IR-induced desorption of CO and N₂ from CO:H2O and N₂:H₂O mixed ices grown at 9 K. These studies were performed at FELIX, the free electron laser facility at Radboud University, Nijmegen, The Netherlands. Irradiation of the ices was performed in the mid-IR range from 2.9–12 µm and shows that photon induced desorption (PID) of CO and N₂ only occurs when the ices are irradiated at wavelengths that excite the vibrational modes of the H₂O ice. No PID is observed when the internal stretching modes of the dopant molecules are excited. The observed PID traces, recorded during the irradiation with a mass spectrometer, can be fitted with a bi-exponential decay function that shows the presence of a fast and a slow photodesorption process. These can be assigned to direct and indirect substrate-mediated resonant photodesorption processes. Power dependence studies show saturation and suggest that a complex process is leading to the observed PID. The data reported here clearly show that IR-driven photodesorption should be considered in astrophysical models.
SN - 1463-9076
SN - 1463-9084
ER -