Related papers: Towards a Solution of the Polycyclic Aromatic Hydr…
We report on an experimental and theoretical investigation of the importance of anharmonicity in the 3 micron CH stretching region of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We present mass-resolved, high-resolution spectra of the…
Two key questions of the chemistry of Polycyclic Aromatic Hydrocarbons (PAHs) in the interstellar medium (ISM) are addressed: i) the way carbon is returned from PAHs to the interstellar gas after the very efficient accretion of C+ ions onto…
The paper describes profile broadening and peak wavelength variation of diffuse interstellar bands (DIBs) measured for 46 lines of sight, probably caused by physical properties of intervening clouds. Full width at half maximum of four…
Diffuse interstellar bands (DIBs) are absorption features commonly observed in optical/near-infrared spectra of stars and thought to be associated with polyatomic molecules that comprise a significant reservoir of organic material in the…
Virtually all detailed gas-phase models of the chemistry of dense interstellar clouds exclude polycyclic aromatic hydrocarbons (PAH's). This omission is unfortunate because from the few studies that have been done on the subject, it is…
The unidentified infrared bands (UIBs) have been observed in virtually every dusty astrophysical environment investigated. The UIB carrier must be abundant and ubiquitous. Strong evidence points to polycyclic aromatic hydrocarbons (PAHs) as…
This paper considers a very special set of a few interstellar features --- broad diffuse interstellar bands (DIBs) at 4430, 4882, 5450, 5779 and 6175 \AA\AA. The set is small, and measurements of equivalent widths of these DIBs are…
One of the major challenges to identification of the 3.3, 6.2, 7.7, 8.6, and 11.3um interstellar IR emission bands with polycyclic aromatic hydrocarbon (PAH) molecules has been the recent detection of these bands in regions with little UV…
It has been an unanswered question how many dusty galaxies have been undetected from the state-of-the-art observational surveys. JWST enables us to detect faint IR galaxies that have prominent polycyclic aromatic hydrocarbon (PAH) features…
Here we report our discovery of a band of blue luminescence (BL) in the Red Rectangle (RR) nebula. This enigmatic proto-planetary nebula is also one of the brightest known sources of extended red emission as well as of unidentified…
There has been a renewed interest in searching for diffuse interstellar bands (DIBs) due to their probable connection to organic molecules and, thus, their possible link to life in the Universe. Our group is undertaking an extensive search…
The aromatic infrared Bands (AIBs) dominate the mid-infrared spectra of many galactic and extragalactic sources. These AIBs are generally attributed to fluorescent emission from aromatic molecules. Unified efforts from experimentalists and…
A careful examination of Red Rectangle bands which have been considered as diffuse interstellar bands (DIBs) in emission shows that a few are likely to be artifacts in the spectrum. Some others result from atmospheric extinction.…
The diffuse interstellar bands (DIBs) are absorption lines observed in visual and near infrared spectra of stars. Understanding their origin in the interstellar medium (ISM) is one of the oldest problems in astronomical spectroscopy, as…
Diffuse interstellar bands (DIBs) are weak absorption features of interstellar origin present in the optical and infrared spectra of stars. Their use as a tool to trace the structure of the Galactic ISM is gaining relevance in the recent…
We present the results of a computational study to investigate the infrared spectroscopic properties of a large number of polycyclic aromatic hydrocarbon (PAH) molecules and their fully dehydrogenated counterparts. We constructed a database…
We investigate the evolution of polycyclic aromatic hydrocarbon (PAH) abundance in a galaxy, which is a crucial step to understand the evolution of bright emission features in the mid-infrared range. We calculate the evolution of dust grain…
Polycyclic aromatic hydrocarbons (PAHs) are some of the major dust components in the interstellar medium (ISM). We present our evolution models for the abundance of PAHs in the ISM on a galaxy-evolution timescale. We consider shattering of…
The life cycle of the population of interstellar polycyclic aromatic hydrocarbon (PAH) molecules depends partly on the photostability of the individual species. We have studied the dissociative photoionization of two ethynyl-substituted PAH…
JWST observations of polycyclic aromatic hydrocarbon (PAH) emission provide some of the deepest and highest resolution views of the cold interstellar medium (ISM) in nearby galaxies. If PAHs are well mixed with the atomic and molecular gas…