Infrared Cooling in an Anharmonic Cascade Framework: 2-Cyanoindene, the Smallest Cyano-PAH Identified in Taurus Molecular Cloud-1.

ABSTRACT: Infrared (IR) cooling of polycyclic aromatic hydrocarbon (PAH) molecules is a major radiative stabilization mechanism of PAHs present in space and is the origin of the aromatic infrared bands (AIBs). Here, we report an anharmonic cascade model in a master equation framework to model IR emission rates and emission spectra of energized PAHs as a function of internal energy. The underlying (simple harmonic cascade) framework for fundamental vibrations has been developed through the modeling of cooling rates of PAH cations and other carboneaous ions measured in electrostatic ion storage ring experiments performed under "molecular cloud in a box" conditions. The anharmonic extension is necessitated because cyano-PAHs, recently identified in Taurus Molecular Cloud-1 (TMC-1), exhibit strong anhar

SUBMITTER: Stockett MH 

PROVIDER: S-EPMC11850017 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature