arXiv subjects

Yash Lenka

Publications and source records attributed to Yash Lenka.

3 recordsLinked to original sources

arXiv2026

Observation of spontaneous N-bearing PAH formation using ion trap: a new formation pathway in the interstellar medium

Nitrogen-bearing polycyclic aromatic hydrocarbons (N-PAHs) are key precursors to complex organic molecules in both the interstellar medium and the nitrogen-rich planetary atmospheres. Despite the recent detections of nitrogen-functionalized astromolecules, their formation pathways remain an open question. The discrepancies between their predicted and observed abundances point to unknown mechanism that govern their evolution in the astrophysical environments. Employing an ion trap technique in conjuction with electronic structure calculations, we unravel multiple barrier-less reactions between gas-phase pyrimidine cations (C$_4$H$_4$N$_2^+$) and acetylene (C$_2$H$_2$) which form a hitherto unreported endocyclic- N-PAHs (C$_8$H$_7$N$_2^+$). The present measurements on reactions involving a double-nitrogen subsituted aromatic heterocycle have implications to the astrochemistry of both the Titan's atmosphere and the interstellar medium.

astro-ph.GA↗

arXiv2024

Photo-induced molecular growth of benzonitrile in the gas phase

Due to the absorption of high energetic ultraviolet (UV) photons by the surface layers of the cold molecular clouds, only low energetic photons are able to penetrate into the inner regions of these clouds. This leads to lower photo-ionization yield of molecules of higher ionization potential in these environments. However, here we have experimentally shown the ionization of Benzonitrile molecule using 266nm (4.66eV) photons. The low intensity and unfocused laser irradiation of benzonitrile molecules results extensive fragmentation. Moreover, the ion-neutral reactions among the cationic fragments and neutral fragments shows promising molecular mass growth.

physics.chem-ph↗

arXiv2023

Collective Energy Transfer to a Spectator Atom via Multi-Center Intermolecular Coulombic Decay

Molecular mechanisms that enable collective and upconverted energy transfer from multiple photoacceptors to a non-absorbing spectator reaction center are highly desirable for efficient light-energy utilization. Here, we show that intermolecular Coulombic decay (ICD), a nonlocal energy relaxation channel in photoexcited molecules, offers an avenue for such a novel energy transfer mechanism. On irradiation of pyridine-argon gas mixture at 266 nm and at low laser intensities, we observed a surprisingly dominant formation of argon cations. Measurements of the laser power dependence, together with systematic studies of Ar$^+$ yield versus laser intensity and molecular density, reveal that ICD mediates the collective funneling of excitation energy from multiple photoexcited pyridine molecules to a non-photoabsorbing argon atom, leading to its ionization. The density of the reaction center offers an efficient handle to optimize this collective energy transfer. This mechanism opens new avenues in light harvesting design and may help explain the remarkable resistance of biomolecules to photodamage.

physics.chem-ph↗