Prof. GAO Hong’s group from Institute of Chemistry, Chinese Academy of Sciences (ICCAS) investigated the collisional energy transfer dynamics between the spin-orbit state-selected Ar⁺(²P_3/2,1/2) ion and N₂ at a collision energy of 1.58eV.

Collisional energy transfer via inelastic scattering between ions and neutrals is crucial in various complex gaseous environments, including planetary atmospheres, interstellar media, combustion, and plasmas. However, detailed experimental investigations of this process pose significant challenges.

Utilizing a home-built quantum-state-selected ion-molecule crossed-beam setup, in collaboration with Prof. GUO Hua and colleagues from the University of New Mexico, the team conducted a combined experimental and theoretical study. This research provides unprecedented insights into the microscopic inelastic scattering mechanism of Ar⁺(2P_3/2,1/2) + N₂ → Ar + N₂⁺(v′, J′).

The findings reveal that all vibrationally excited N₂ products resulting from collisions with Ar⁺ ions are predominantly the result of forward scattering, challenging traditional textbook models. The trajectory surface-hopping (TSH) calculations corroborated these observations and indicated that vibrational excitation primarily occurs through a transient charge-transfer process.

Moreover, the study identifies a hard collision glory mechanism, previously observed only in inelastic rotational energy transfer between neutrals, as a significant factor in vibrational excitation during Ar⁺ + N₂ collisions, mediated by a frustrated charge transfer process.

This research underscores the effectiveness of the ion-molecule crossed-beam setup with quantum state-selected ion sources as a powerful tool for exploring collisional energy transfer dynamics between ions and neutrals.

Product scattering images and calculated angular distributions for Ar⁺(²P_3/2) + N₂ → Ar⁺ + N₂(v′, J′) (a, b) and Ar⁺(²P_1/2) + N₂ → Ar⁺ + N₂(v′, J′) (c, d), respectively

The study entitled “Frustrated charge transfer in vibrationally inelastic Ar⁺+N₂ collisions via hard collision glory scattering” was published in Nature Communications(DOI: 10.1038/s41467-024-52530-z).

Contact:

Prof. GAO Hong

Institute of Chemistry, Chinese Academy of Sciences

Email: honggao2017@iccas.ac.cn