Nag, S and Majumdar, J and Sivaraman, B and Yashonath, S and Maiti, PK (2023) Influence of the substrate on the density and infrared spectra of the adsorbed methanol ice of different thicknesses using molecular dynamics simulation. In: Monthly Notices of the Royal Astronomical Society, 522 (3). pp. 3656-3664.
Full text not available from this repository.Abstract
In the interstellar medium, several complex organic molecules are found, and of these molecules, methanol is the simplest and the most ubiquitous one. By comparing the observed infrared (IR) spectra from astrochemical data, with laboratory experiments, one can deduce the composition and structure of these astrochemical ices. Computational studies are scarce, yet they could be greatly helpful in understanding the nature of these molecules. On that premise, the present study reports a molecular dynamics study of adsorbed methanol on the KBr substrate at 90 K and 130 K. After validating the potential parameters, two adsorbed phases differing in their thickness along the z-axis: 4 × 10 × 4 (4 layers) and 4 × 10 × 50 (50 layers) were simulated. Depending on this thickness, the IR spectra and density distribution functions were computed for the bottom and top 10 Å of the 4 layers of adsorbed methanol and the top, middle, and bottom 10 Å of the 50 layers of adsorbed methanol on the KBr substrate. The bottom 10 Å of the adsorbed phase exhibit considerable disorder. Additionally, the bands in the IR spectra of these bottom 10 Å show widening, referring to a heterogeneous environment. It is further reported that the slower heating and cooling of the adsorbed phase between 90 K and 130 K leads to a complete reversal of the changes seen in heating. Our findings here further clarify the recent observation of the amorphous phase of different astrochemical molecules seen at low temperatures and their crystalline phase seen at relatively higher temperatures.
| Item Type: | Journal Article |
|---|---|
| Publication: | Monthly Notices of the Royal Astronomical Society |
| Publisher: | Oxford University Press |
| Additional Information: | The copyright for this article belongs to Oxford University Press |
| Keywords: | Bromine compounds; Computer software; Distribution functions; Molecular dynamics; Molecules; Potassium compounds, Adsorbed phasis; Astrochemistry; Density spectrum; Different thickness; Infrared spectrum; Infrared: general; ISM:molecules; Methods:statistical; Molecular data; Software simulation, Methanol |
| Department/Centre: | Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Physical & Mathematical Sciences > Physics |
| Date Deposited: | 16 Jun 2023 09:08 |
| Last Modified: | 16 Jun 2023 09:08 |
| URI: | https://eprints.iisc.ac.in/id/eprint/82028 |
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