| Name: | Venkata Lakshmi |
| Affiliation: | GITAM Deemed to be University, Hyderabad |
| Conference ID: | ASI2025_45 |
| Title: | Theoretical anharmonic infrared and ultraviolet spectroscopic study of interstellar PAHs upto ten hexagons |
| Authors: | Venkata Lakshmi Karri A1,
Mahadevappa Naganathappa A2*
|
| Authors Affiliation: | A1 Ph.D third year student, Department of Physics, School of Science, GITAM (Deemed to be University), Hyderabad 502329 (TS) India
A2 Associate Professor, Department of Physics, School of Science, GITAM (Deemed to be University), Hyderabad 502329 (TS) India |
| Mode of Presentation: | Poster |
| Abstract Category: | Stars, Interstellar Medium, and Astrochemistry in Milky Way |
| Abstract: | The present study reports a comparison of theoretical harmonic and anharmonic infrared and optical absorption spectra of 01 to 10 hexagons PAHs in their neutral and ionic states with observations. The PAHs (polycyclic aromatic hydrocarbons) which is the most abundant and play an important role in the physics and chemistry of the astronomical environment. They are primarily responsible for the aromatic infrared bands (AIBs) observed in various regions of the interstellar medium (ISM). This study will be focus is on identifying the potential carriers of the AIBs and understanding their significance in the 217.5 nm astronomical UV bump. The 01 to 10 hexagon structural arrangements are considered in cata- and peri-condensed form. All these structures are optimized at the B3LYP/6-311++G (d) level of theory to confirm the lowest energy structure. The analysis of harmonic to anharmonic vibrational spectra computations results in minor changes in PAH MIR spectral characteristics. We use the advanced capability of MIRI JWST telescopes to obtain observational data for the comparison. This study gives the understanding of the physical and chemical processes of cosmic dust and PAHs in diverse astronomical environments. We have also compared the UV bump features at 217.5 nm with the obtained electronic absorption spectra of 01 to 10 hexagons in their neutral and their ionic states using time-dependent density functional theory (TDDFT) at the same level of theory. |
