Theoretical Spectroscopic Study of Isopropyl Alcohol (CH3-CHOH-CH3)

Accurate spectroscopic parameters of isopropyl alcohol, a volatile organic compound present on Earth and in extraterrestrial atmospheres, are provided. The work pursues the study of the far-infrared region, describing the distribution of the low-lying vibrational energy levels that can be populated...

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Main Authors: Mohammed Salah, Khadija Marakchi, Najia Komiha, Maria Luisa Senent
Format: Article
Language:English
Published: IOP Publishing 2024-01-01
Series:The Astrophysical Journal
Subjects:
Online Access:https://doi.org/10.3847/1538-4357/ad1fef
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author Mohammed Salah
Khadija Marakchi
Najia Komiha
Maria Luisa Senent
author_facet Mohammed Salah
Khadija Marakchi
Najia Komiha
Maria Luisa Senent
author_sort Mohammed Salah
collection DOAJ
description Accurate spectroscopic parameters of isopropyl alcohol, a volatile organic compound present on Earth and in extraterrestrial atmospheres, are provided. The work pursues the study of the far-infrared region, describing the distribution of the low-lying vibrational energy levels that can be populated at very low temperatures, having effects on the detectability and identification. The potential energy surface shows 27 almost equivalent minima producing 27 subcomponents of the levels due to tunneling effects. Computations have been performed using highly correlated ab initio calculations, accurate enough to distinguish between the rotational parameters of the two quasi-identical conformers gauche and trans. A variational procedure in three dimensions depending on three interacting internal rotations, the internal rotation of the two methyl groups and the internal rotation of the hydroxyl group, is employed to compute the energies. The 27 subcomponents of the ground vibrational state can be grouped into three series of nine energy levels located around 0.000, 1.693, and 81.927 cm ^−1 whose energy difference is due to the OH torsion effect. The nine subcomponents integrated in each series derive from the torsion of the two methyl groups. The computations reproduce accurately the available experimental data. New predicted properties can help the spectroscopic analysis of the rotational-vibrational spectra in the gas phase and further detections of vibrationally excited isopropyl alcohol.
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spelling doaj.art-1346e01af8f34745b4f3704ba452e3692024-03-12T13:55:32ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-01963214310.3847/1538-4357/ad1fefTheoretical Spectroscopic Study of Isopropyl Alcohol (CH3-CHOH-CH3)Mohammed Salah0Khadija Marakchi1Najia Komiha2Maria Luisa Senent3https://orcid.org/0000-0003-1878-7377Laboratory of Spectroscopy, Molecular Modeling, Materials, Nanomaterials, Water and Environment, “LS3MN2E/CERNE2D”, Mohammed V University in Rabat , Faculty of Sciences, Morocco; Molecular Modeling and Spectroscopy Research Team, Department of Chemistry, Faculty of Sciences, Chouaïb Doukkali University , El Jadida, MoroccoLaboratory of Spectroscopy, Molecular Modeling, Materials, Nanomaterials, Water and Environment, “LS3MN2E/CERNE2D”, Mohammed V University in Rabat , Faculty of Sciences, MoroccoLaboratory of Spectroscopy, Molecular Modeling, Materials, Nanomaterials, Water and Environment, “LS3MN2E/CERNE2D”, Mohammed V University in Rabat , Faculty of Sciences, MoroccoDepartamentode Química y Física Teóricas, Instituto de Estructura de la Materia , IEM-CSIC, Serrano 121, Madrid 28006; Unidad Asociada GIFMAN, CSIC-UHU, Spain ; senent@iem.cfmac.csic.es, ml.senent@csic.esAccurate spectroscopic parameters of isopropyl alcohol, a volatile organic compound present on Earth and in extraterrestrial atmospheres, are provided. The work pursues the study of the far-infrared region, describing the distribution of the low-lying vibrational energy levels that can be populated at very low temperatures, having effects on the detectability and identification. The potential energy surface shows 27 almost equivalent minima producing 27 subcomponents of the levels due to tunneling effects. Computations have been performed using highly correlated ab initio calculations, accurate enough to distinguish between the rotational parameters of the two quasi-identical conformers gauche and trans. A variational procedure in three dimensions depending on three interacting internal rotations, the internal rotation of the two methyl groups and the internal rotation of the hydroxyl group, is employed to compute the energies. The 27 subcomponents of the ground vibrational state can be grouped into three series of nine energy levels located around 0.000, 1.693, and 81.927 cm ^−1 whose energy difference is due to the OH torsion effect. The nine subcomponents integrated in each series derive from the torsion of the two methyl groups. The computations reproduce accurately the available experimental data. New predicted properties can help the spectroscopic analysis of the rotational-vibrational spectra in the gas phase and further detections of vibrationally excited isopropyl alcohol.https://doi.org/10.3847/1538-4357/ad1fefInterstellar medium
spellingShingle Mohammed Salah
Khadija Marakchi
Najia Komiha
Maria Luisa Senent
Theoretical Spectroscopic Study of Isopropyl Alcohol (CH3-CHOH-CH3)
The Astrophysical Journal
Interstellar medium
title Theoretical Spectroscopic Study of Isopropyl Alcohol (CH3-CHOH-CH3)
title_full Theoretical Spectroscopic Study of Isopropyl Alcohol (CH3-CHOH-CH3)
title_fullStr Theoretical Spectroscopic Study of Isopropyl Alcohol (CH3-CHOH-CH3)
title_full_unstemmed Theoretical Spectroscopic Study of Isopropyl Alcohol (CH3-CHOH-CH3)
title_short Theoretical Spectroscopic Study of Isopropyl Alcohol (CH3-CHOH-CH3)
title_sort theoretical spectroscopic study of isopropyl alcohol ch3 choh ch3
topic Interstellar medium
url https://doi.org/10.3847/1538-4357/ad1fef
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AT khadijamarakchi theoreticalspectroscopicstudyofisopropylalcoholch3chohch3
AT najiakomiha theoreticalspectroscopicstudyofisopropylalcoholch3chohch3
AT marialuisasenent theoreticalspectroscopicstudyofisopropylalcoholch3chohch3