Electron-driven molecular processes for cyanopolyacetylenes HCN ( = 3, 4, and 5).

Linear carbon series cyanopolyacetylenes (HCN) ( = 3, 4, and 5) are astromolecules found in the atmosphere of Titan and interstellar media such as TMC-1 (Taurus molecular cloud-1). All these compounds are also detected in IRC + 10 216. In the present work, we comprehensively investigate electron interaction with important cyanopolyacetylene compounds, HCN (cyano-tri-acetylene), HCN (cyano-tetra-acetylene), and HCN (cyano-penta-acetylene). The study covers incident electron energies ranging from the ionization threshold to 5 keV. Various electron-driven molecular processes are quantified in terms of total cross-sections. The quantum spherical complex optical potential (SCOP) is used to determine elastic () and inelastic () cross-sections. Ionization is the most important inelastic effect that opens various chemical pathways for the generation of different molecular species; we computed the ionization cross-section () and discrete electronic excitation cross-section (Σ) using the complex scattering potential-ionization contribution (CSP-ic) method. The cyanopolyacetylene compounds are difficult to handle experimentally owing to the health risks involved. Therefore, there are no prior experimental data available for these molecules; only have been reported theoretically. Thus, the present work is the maiden report on computing , , Σ, and . In order to provide an alternative approach and further validation of the present work, we employed our recently developed two-parameter semi-empirical method (2p-SEM) to compute and . Additionally, we predict the polarizability of the HCN molecule, which has not been reported in the existing literature. This prediction is based on a correlation study of polarizabilities of molecules with values from the same series of molecules.