Phase Space Electronic Structure Theory: From Diatomic Lambda-Doubling to Macroscopic Einstein-de Haas

Fuente: arXiv
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Main Authors: Peng, Linqing, Qiu, Tian, Bradbury, Nadine, Bian, Xuezhi, Bhati, Mansi, Littlejohn, Robert, Kidwell, Nathanael M., Subotnik, Joseph E.
Format: Preprint
Published: 2025
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_version_ 1866912842457808896
author Peng, Linqing
Qiu, Tian
Bradbury, Nadine
Bian, Xuezhi
Bhati, Mansi
Littlejohn, Robert
Kidwell, Nathanael M.
Subotnik, Joseph E.
author_facet Peng, Linqing
Qiu, Tian
Bradbury, Nadine
Bian, Xuezhi
Bhati, Mansi
Littlejohn, Robert
Kidwell, Nathanael M.
Subotnik, Joseph E.
contents $Λ$-doubling of diatomic molecules is a subtle microscopic phenomenon that has long attracted the attention of experimental groups, insofar as rotation of molecular $\textit{nuclei}$ induces small energetic changes in the (degenerate) $\textit{electronic}$ state. A direct description of such a phenomenon clearly requires going beyond the Born-Oppenheimer approximation. Here we show that a phase space theory previously developed to capture electronic momentum and model vibrational circular dichroism -- and which we have postulated should also describe the Einstein-de Haas effect, a macroscopic manifestation of angular momentum conservation -- is also able to recover the $Λ$-doubling energy splitting (or $Λ$-splitting) of the NO molecule nearly quantitatively. The key observation is that, by parameterizing the electronic Hamiltonian in terms of both nuclear position ($\mathbf{X}$) and nuclear momentum ($\mathbf{P}$), a phase space method yields potential energy surfaces that explicitly include the electron-rotation coupling and correctly conserve angular momentum (which we show is essential to capture $Λ-$doubling). The data presented in this manuscript offers another small glimpse into the rich physics that one can learn from investigating phase space potential energy surfaces $E_{PS}(\mathbf{X},\mathbf{P})$ as a function of both nuclear position and momentum, all at a computational cost comparable to standard Born-Oppenheimer electronic structure calculations.
format Preprint
id arxiv_https___arxiv_org_abs_2512_13448
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Phase Space Electronic Structure Theory: From Diatomic Lambda-Doubling to Macroscopic Einstein-de Haas
Peng, Linqing
Qiu, Tian
Bradbury, Nadine
Bian, Xuezhi
Bhati, Mansi
Littlejohn, Robert
Kidwell, Nathanael M.
Subotnik, Joseph E.
Chemical Physics
Atomic Physics
Quantum Physics
$Λ$-doubling of diatomic molecules is a subtle microscopic phenomenon that has long attracted the attention of experimental groups, insofar as rotation of molecular $\textit{nuclei}$ induces small energetic changes in the (degenerate) $\textit{electronic}$ state. A direct description of such a phenomenon clearly requires going beyond the Born-Oppenheimer approximation. Here we show that a phase space theory previously developed to capture electronic momentum and model vibrational circular dichroism -- and which we have postulated should also describe the Einstein-de Haas effect, a macroscopic manifestation of angular momentum conservation -- is also able to recover the $Λ$-doubling energy splitting (or $Λ$-splitting) of the NO molecule nearly quantitatively. The key observation is that, by parameterizing the electronic Hamiltonian in terms of both nuclear position ($\mathbf{X}$) and nuclear momentum ($\mathbf{P}$), a phase space method yields potential energy surfaces that explicitly include the electron-rotation coupling and correctly conserve angular momentum (which we show is essential to capture $Λ-$doubling). The data presented in this manuscript offers another small glimpse into the rich physics that one can learn from investigating phase space potential energy surfaces $E_{PS}(\mathbf{X},\mathbf{P})$ as a function of both nuclear position and momentum, all at a computational cost comparable to standard Born-Oppenheimer electronic structure calculations.
title Phase Space Electronic Structure Theory: From Diatomic Lambda-Doubling to Macroscopic Einstein-de Haas
topic Chemical Physics
Atomic Physics
Quantum Physics
url https://arxiv.org/abs/2512.13448