Formation of formaldehyde through methanol-ice-mantle (CH₃OH)₁₀ bombardment by OH⁺ cation

¹ Universidad Autónoma de Chile, Facultad de Ingeniería, Instituto de Ciencias Químicas Aplicadas, Núcleo de Astroquímica & Astrofísica, Av. Pedro de Valdivia 425, Providencia, Santiago, Chile
e-mail: natalia.inostroza@uautonoma.cl
² Universidad Autónoma de Chile, Facultad de Ingeniería, Instituto de Ciencias Químicas Aplicadas, Núcleo de Astroquímica & Astrofísica, Av. Alemania, 01090 Temuco, Chile
³ Universidad de Chile, Facultad de Ciencias Físicas y Matemáticas, Departamento de Astronomía, Camino el Observatorio 1515, Las condes, Santiago, Chile
⁴ Universidad de Chile, Facultad de Ciencias Químicas y Farmacéuticas, Dr. Carlos Lorca Tobar 964, Independencia, Santiago, Chile
⁵ Chinese Academy of Sciences South America Center for Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, PR China

Received: 28 January 2021
Accepted: 9 April 2021

Abstract

Context. Formaldehyde H₂CO was the first organic polyatomic molecule discovered in the interstellar medium to have been detected in a variety of sources. However, pathways to synthesize this molecule under interstellar conditions have yet to be discussed.

Aims. We carried out a systematic study to analyze the chemical processes that can explain the H₂CO formation mechanism toward a decamer of methanol (CH₃OH)₁₀ as target material to mimic an ice mantle bombarded by an OH⁺ cation.

Methods. We performed Born-Oppenheimer (ab initio) molecular dynamics simulations to obtain the formation mechanisms of complex organic molecules (COMs) such as formaldehyde H₂CO and its HCOH isomer.

Results. We found that CH₂OH⁺ and CH₂(OH)₂ are the main precursors to form H₂CO and HCOH. We discuss its formation mechanisms and the astrophysical implications in star-forming regions. These processes are likely relevant to the production of COMs.