Molecular photodissociation in the vacuum ultraviolet region: implications for astrochemistry and planetary atmospheric chemistry

Abstract

Vacuum ultraviolet (VUV) photons with wavelengths shorter than ∼200 nm play a critical role in the interstellar, circumstellar and planetary atmospheric chemistries. Photodissociation of parent molecular species after absorbing VUV photons usually produces smaller molecules in rotational, vibrational and electronic excited states, and these excited daughter species could be extremely reactive, and trigger the complex chemical networks in these environments. Detailed quantum state-to-state investigations of the various VUV photodissociation processes by using cutting-edge experimental techniques can provide critical information for accurately modelling the chemical properties of the interstellar and circumstellar mediums and planetary atmospheres. This article will highlight several recent works of VUV photodissociation, which utilised state-of-the-art experimental techniques and provided important implications for deepening our understanding of the chemical properties of the relevant environments. Furthermore, several future research directions and the challenges faced will be proposed and discussed, where quantum state-to-state molecular photodissociation studies in the VUV region can provide key information needed for accurate chemical modelling and understanding of the astronomical observations.