Production of H ₃ ⁺ and D ₃ ⁺ from (CH ₃)₂ CO and (CD ₃)₂ CO in PDR’S

Abstract

Acetone ((CH₃)₂CO) was the first 10 atom molecule reported in the interstellar medium. The confirmation of acetone has been recently reported in the giant molecular cloud Sgr B2, which undergoes extensive star formation [1]. Chemistry in Sgr B2 has been strongly modified by the photons coming from the hot stars in the nebulae. The formation of H ₃ ⁺ through photoionization and photodissociation processes of abundant interstellar organic molecules like (CH₃)₂CO plays an important role in diverse fields from chemistry to astronomy [2]. As an example we mention the chains of reaction that lead to the production of many complex molecular species observed in the interstellar medium [3]. H ₃ ⁺ was recently discovered both in molecular clouds [4] and in the diffuse interstellar medium [5].