ON THE NIR-VIS SPECTROSCOPY OF NO2: POTENTIAL ENERGY CURVES OF THE X²A₁, A²B₂, B²B₁, and C²A₂ STATES AND THE òB₂-X̃²A₁ CONICAL INTERSECTION

Vázquez, Gabriel J.

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https://hdl.handle.net/2142/122709 Copy

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Title

ON THE NIR-VIS SPECTROSCOPY OF NO2: POTENTIAL ENERGY CURVES OF THE X²A₁, A²B₂, B²B₁, and C²A₂ STATES AND THE òB₂-X̃²A₁ CONICAL INTERSECTION

Author(s)

Vázquez, Gabriel J.

Contributor(s)

• Atabek, OSMAN
• Serov, Vassili N.
• Liebermann, Hans-Peter
• Amero, José M.
• Alcantar, Carolina Godoy

Issue Date

2023-06-21

Keyword(s)

Atmospheric science

Abstract

Ab initio SCF MRD–CI electronic structure calculations are carried out in Cs symmetry for the three lowest ²A′ and ²A" states of NO₂. The four lowest-lying species correspond, respectively, to X²A₁(1²A′), A²B₂(2²A′), B²B₁(1²A") and C²A₂(2²A") in C₂v symmetry. A cc–pVQZ basis set augmented with s, p, and d Rydberg functions is employed together with an extensive treatment of electron correlation. One–dimensional (1D) potential energy curves (PECs), associated to the equilibrium geometrical parameters of the X²A₁ ground state (GS), were computed for the four aforementioned doublet states located in the near-IR and visible regions. These 1D cuts are related loosely to the bending, symmetric stretch and asymmetric stretch vibrational modes of the GS. The PECs are then employed to discuss the NIR-Vis absorption/emission spectroscopy of NO₂ and the strong conical intersection (CI) between the ground and first excited A²B₂ states. In spite of being a small triatomic made up of 2nd-row atoms only, NO₂, a relatively ”simple” molecule turns out to be an important testing ground for the study of a number of fundamental molecular processes such as the dynamics of intramolecular energy redistribution which involves the coupling of electronic and nuclear motions and entails the breakdown of the adiabatic BO approximation (e.g., the ÖX̃ conical intersection, Renner-Teller interactions, electronic-to-vibrational (EV) energy transfer, relaxation of vibrational energy), and for studies of the dynamics of photodissociation/predissociation and photoionization/autoionization. The NO₂ PECs reported in this work may be instrumental to visualize some of the above processes.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Handle URL

https://hdl.handle.net/2142/122709

DOI

https://doi.org/10.15278/isms.2023.7267

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