2500 vibronic eigenstates of the NO$_3$ radical

Fuente: arXiv
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Main Authors: Larsson, Henrik R., Viel, Alexandra
Format: Preprint
Published: 2024
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author Larsson, Henrik R.
Viel, Alexandra
author_facet Larsson, Henrik R.
Viel, Alexandra
contents The nitrate radical NO$_3$ plays an important role in atmospheric chemistry, yet many aspects of its coupled and anharmonic vibronic structure remain elusive. Here, using an accurate, coupled full-dimensional diabatic potential that includes five electronic states, we revisit the vibronic spectrum associated with the electronic $\tilde X ^2A_2'$ state. Using recently developed tensor network state methods, we are able to compute more than 2500 vibronic states, thereby increasing the number of computed full-dimensional states by a factor of 50, compared to previous work. While we obtain good agreement with experiment for most of the assigned vibronic levels, for several others, we observe striking disagreement. Further, for the antisymmetric bending motion we find remarkably large symmetry-induced level splittings that are larger than the zero-order reference. We discuss non-negligible nonadiabatic effects and show that the Born-Oppenheimer approximation leads to significant errors in the spectrum.
format Preprint
id arxiv_https___arxiv_org_abs_2407_03398
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle 2500 vibronic eigenstates of the NO$_3$ radical
Larsson, Henrik R.
Viel, Alexandra
Chemical Physics
Computational Physics
Quantum Physics
The nitrate radical NO$_3$ plays an important role in atmospheric chemistry, yet many aspects of its coupled and anharmonic vibronic structure remain elusive. Here, using an accurate, coupled full-dimensional diabatic potential that includes five electronic states, we revisit the vibronic spectrum associated with the electronic $\tilde X ^2A_2'$ state. Using recently developed tensor network state methods, we are able to compute more than 2500 vibronic states, thereby increasing the number of computed full-dimensional states by a factor of 50, compared to previous work. While we obtain good agreement with experiment for most of the assigned vibronic levels, for several others, we observe striking disagreement. Further, for the antisymmetric bending motion we find remarkably large symmetry-induced level splittings that are larger than the zero-order reference. We discuss non-negligible nonadiabatic effects and show that the Born-Oppenheimer approximation leads to significant errors in the spectrum.
title 2500 vibronic eigenstates of the NO$_3$ radical
topic Chemical Physics
Computational Physics
Quantum Physics
url https://arxiv.org/abs/2407.03398