Title :

Absolute photoabsorption cross-sections of methanol for terrestrial and astrophysical relevance

Author(s) :

Lange, Emanuele [Auteur]
Lozano, Ana Isabel [Auteur]
Jones, Nykola [Auteur]
Centre for Storage Ring Facilities [Aarhus] [ISA]
Hoffmann, Søren Vrønning Vrønning [Auteur]
Centre for Storage Ring Facilities [Aarhus] [ISA]
Kumar, Sarvesh [Auteur]
Śmiałek-Telega, Malgorzata Anna [Auteur]
Duflot, Denis [Auteur correspondant]
Physico-Chimie Moléculaire Théorique [PCMT]
Brunger, Michael [Auteur]
Limao-Vieira, Paulo [Auteur correspondant]

Journal title :

Journal of Physical Chemistry A

Pages :

8496-8508

Publisher :

American Chemical Society

Publication date :

2020-10-15

ISSN :

1089-5639

HAL domain(s) :

Chimie/Chimie théorique et/ou physique
Physique [physics]/Physique [physics]/Chimie-Physique [physics.chem-ph]

English abstract : [en]

We investigate the methanol absorption spectrum in the range 5.5–10.8 eV in order to provide accurate and absolute cross-sections values. The main goal of this study is to provide a comprehensive analysis of methanol’s ...
Show more >We investigate the methanol absorption spectrum in the range 5.5–10.8 eV in order to provide accurate and absolute cross-sections values. The main goal of this study is to provide a comprehensive analysis of methanol’s electronic state spectroscopy by employing high-resolution vacuum ultraviolet (VUV) photoabsorption measurements together with state-of-the art quantum chemical calculation methods. The VUV spectrum reveals several new features that are not previously reported in the literature, for n > 3 in the transitions (nsσ(a')←(2a")) (¹A'←X¹A') and (nsσ, npσ, nsσ', ndσ ← (7a')) (¹1A' ← X¹A'), and with particular relevance to vibrational progressions of the CH₃ rocking mode, ν'₁₁ (a"), mode in the (3pπ(a")←(2a")) (¹A' ← X¹A') absorption band at 8.318 eV. The measured absolute photoabsorption cross sections have subsequently been used to calculate the photolysis lifetime of methanol in the Earth’s atmosphere from the ground level up to the limit of the stratosphere (50 km altitude).This shows that solar photolysis plays a negligible role in the removal of methanol from the lower atmosphere compared with competing sink mechanisms. Torsional potential energy scans, as a function of the internal rotation angle for the ground and first Rydberg states have also been calculated as part of this investigationShow less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

ANR Project :

Physiques et Chimie de l'Environnement Atmosphérique
ULNE

Collections :

• Laboratoire de Physique des Lasers, Atomes et Molécules (PhLAM) - UMR 8523

Source :

Harvested from HAL