Interactions and dynamics of metastable triplet-state helium dimer with Ne and Ar
Abstract
Helium dimer in its metastable triplet electronic state, He2(a 3Σu+), is a promising candidate for direct laser cooling and precision measurements. Interactions and collisions involving He2(a 3Σu+) remain unexplored in ultracold and cold energy domains. Here, we present the first theoretical investigation of intermolecular interactions and collision dynamics of He2(a 3Σu+)+Ne van der Waals complex. For the ground electronic state, X 3A', we employ a spin-restricted coupled cluster method with single, double, and noniterative triple excitations. The resulting interaction potential exhibits an extremely shallow well with a depth of 4.612 cm−1. We construct a three-dimensional vibrationally averaged potential energy surface. Using this surface, we perform full close-coupling calculations including fine-structure levels of He2(a 3Σu+) to investigate collisional excitation and quenching induced by Ne. We analyze the low-energy scattering dynamics and model resonant features associated with quasi-bound states supported by interaction potential. Propensity rule for fine-structure conserving transitions is established. We additionally consider He2+Ar collisions and compare their energy dependence and resonance structure with those of He2+Ne. The He2+Ar system exhibits a richer resonance structure, highlighting the sensitivity of low-energy scattering to interaction potential and reduced mass. Calculated PES and scattering properties provide a reliable benchmark for description of He2+Ne van der Waals complex and may be useful for interpretation of future experimental spectra and collision measurements.
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BibTeX
@misc{sardar2026interactions,
title = {{Interactions and dynamics of metastable triplet-state helium dimer with Ne and Ar}},
author = {Dibyendu Sardar and François Lique},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.34713},
eprint = {2609.34713},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.34713},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Interactions and dynamics of metastable triplet-state helium dimer with Ne and Ar
AU - Dibyendu Sardar
AU - François Lique
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2609.34713
UR - https://arxiv.org/abs/2609.34713
AB - Helium dimer in its metastable triplet electronic state, He_2(a ^3Σ_u^+), is a promising candidate for direct laser cooling and precision measurements. Interactions and collisions involving He_2(a ^3Σ_u^+) remain unexplored in ultracold and cold energy domains. Here, we present the first theoretical investigation of intermolecular interactions and collision dynamics of He_2(a ^3Σ_u^+)+Ne van der Waals complex. For the ground electronic state, X ^3A', we employ a spin-restricted coupled cluster method with single, double, and noniterative triple excitations. The resulting interaction potential exhibits an extremely shallow well with a depth of 4.612 cm^−1. We construct a three-dimensional vibrationally averaged potential energy surface. Using this surface, we perform full close-coupling calculations including fine-structure levels of He_2(a ^3Σ_u^+) to investigate collisional excitation and quenching induced by Ne. We analyze the low-energy scattering dynamics and model resonant features associated with quasi-bound states supported by interaction potential. Propensity rule for fine-structure conserving transitions is established. We additionally consider He_2+Ar collisions and compare their energy dependence and resonance structure with those of He_2+Ne. The He_2+Ar system exhibits a richer resonance structure, highlighting the sensitivity of low-energy scattering to interaction potential and reduced mass. Calculated PES and scattering properties provide a reliable benchmark for description of He_2+Ne van der Waals complex and may be useful for interpretation of future experimental spectra and collision measurements.
ER -