AlCl分子の双極子モーメントの長年の謎を解明（Decades-old mystery of AlCl dipole moment resolved）

2025-06-11 カリフォルニア大学リバーサイド校（UCR）

＜関連情報＞

• https://news.ucr.edu/articles/2025/06/11/decades-old-mystery-alcl-dipole-moment-resolved
• https://journals.aps.org/pra/abstract/10.1103/hwwm-1mn7#supplemental

スタークレベル分光法によるAlClの電気双極子モーメントの測定 Measurement of the electric dipole moment of AlCl by Stark-level spectroscopy

Li-Ren Liu, Miguel Aguirre, Jr., Stephen R. Kane, Brian K. Kendrick, and Boerge Hemmerling
Physical Review A  Published: 10 June, 2025
DOI: https://doi.org/10.1103/hwwm-1mn7

Abstract

We report the measurement of the electric dipole moment of aluminum monochloride (AlCl) using a cryogenic buffer-gas beam source. Using Stark shift spectroscopy, we derive values for the dipole moments in the body-fixed frame of the two lowest vibrational states for the ¹⁢Σ⁺ electronic state, (′′=0)=−1.679 D and (′′=1)=−1.761 D, and for the ¹⁢Π state, (′=0)=−1.030 D and (′=1)=−1.052 D. We also show that the ab initio calculations of the dipole moment and energy of AlCl are sensitive to the level of treatment of the spin-orbit orbit coupling. We further lay out the implications of these results for astrophysical models of stellar and planetary evolution that have used a substitute value for the dipole moment of AlCl until now.