The Reactions of H and D Atoms with Thin Films of Formaldehyde and Methanol at Cryogenic Temperatures

• Published in: The Astrophysical journal 2005-02, Vol.620 (1), p.542-551
• Main Authors: Hiraoka, Kenzo, Wada, Akira, Kitagawa, Hidekazu, Kamo, Masato, Unagiike, Hayato, Ueno, Toshiyuki, Sugimoto, Takaaki, Enoura, Taeko, Sogoshi, Norihito, Okazaki, Shigemitsu
• Format: Article
• Language: English
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1086/426958

The reactions of H and D atoms with solid formaldehyde (H sub(2)CO) and methanol (CH sub(3)OH) were investigated in the temperature region of 10-30 K. From the reaction of H with solid H sub(2)CO at 10 K, CO, CH sub(3)OH, and paraformaldehyde (polyoxymethylene) were the major products, with yields of about 1% or less under the experimental conditions. The yields of these products decrease steeply with an increase in temperature, and they become negligible at 625 K. From the reaction of D with solid H sub(2)CO at 10 K, CO, HDCO, CH sub(2)DOD, and paraformaldehyde were formed. The branching ratio of the reaction [D + HCO 1 CO + HD] to [D + HCO 1 HDCO] was measured to be about 1: 6. The ratio of the yield of CH sub(3)OH from the reaction [H + H sub(2)CO] to that of CH sub(2)DOD from the reaction [D + H sub(2)CO] is 67: 1; i.e., there is a marked isotope effect on the addition reaction of H and D to H sub(2)CO. In the reaction of H and D with CH sub(3)OH, H sub(2)CO was not detected as a reaction product.