Collisional charge transfer reactions (CCTRs) are widely found in complex gas-phase environments such as interstellar medium, planetary atmospheres, and plasmas, etc. Exploring the mechanisms of CCTRs at the molecular level is scientifically important to analyze the matter evolution and energy transfer processes in these complex gas-phase environments.Ar plus plus N2 → Ar plus N2 plus is the classical model system for investigating the dynamics of CCTRs, and it has been extensively investigated experimentally and theoretically over the past half century. experimental and theoretical studies in the past half century. However, the knowledge of the charge transfer mechanism at the molecular level of this model system is limited due to the controversy between different experimental studies and the lack of agreement between experimental and theoretical calculations. This is due to the relatively low energy resolution of product probing in previous experiments, which makes it difficult to obtain the quantum state distribution of the reaction products; in previous experiments, the reactant ion beams contained both spin-orbit quantum states of Ar plus ions, i.e., the ground state Ar plus (2P3/2) and the excited state Ar plus (2P1/2), making it difficult to distinguish between different spin -orbital states of Ar plus ions to the relative contributions of the reaction products.
Gao Hong% 27s група % 2c a изследовател в лабораторията на молекулярна реакция динамика % 2c институт на химия % 2c китайски академия на науки% 2c независимо проектиран и построен а квант състояние селективен йонна молекула напречен лъч устройство. Неговата енергия резолюция достига на водещ ниво на подобни инструменти в света Това проучване е на първо да се използва лазер йонизация да се подготви висока чистота импулсен йон лъчи в специфични квантови състояния. Кинетичната енергия на йонния лъч е непрекъснато регулируема в диапазона на 1.{% 7b5% 7d% 7d.{{6}% 7d eV% 2c с a кинетична енергия разпространение на % 7b% 7b7% 7d% 7d meV . Междувременно% 2c екипът проектиран a триизмерен йон скорост изображения система% 2c което може едновременно реализира скоростта фокусиране и времето фокусиране на продукта йони % 2c с a скорост разделителна способност на нагоре до 1.5 процента .
Recently, the team has made important progress in the study of the spin-orbit state-selected charge transfer reaction Ar plus (2P3/2) ＋ N2 → Ar ＋ N2 plus (v′, J′). In this study, a pulsed ion beam of Ar plus (2P3/2) in the spin-orbit ground state with a purity better than 97 percent was prepared using a resonance-enhanced multiphoton ionization method. The ion beam reaches the reaction center after decelerated focusing, crosses perpendicularly with the collimated N2 ultrasonic molecular beam and undergoes a charge transfer reaction. The three-dimensional velocity distribution of the reaction product N2 plus ions was precisely measured by a three-dimensional ion velocity imaging device. The experiment yielded the best-resolved scattering images to date (Fig. a), and for the first time, the vibrational and transdynamic distributions of the product N2 plus ions and their correlation with the scattering angle were accurately measured. Professor Hua Guo and Dr. Dandan Lu of the University of New Mexico, USA, carried out full-dimensional trajectory surface hopping calculations on the reaction system. The calculations reached a semi-quantitative agreement with the experimental results, revealing for the first time the strong product vibrational dynamics-dependent charge transfer mechanism of the reaction (Figs. b-d). It is shown that the reaction has two completely different charge transfer mechanisms simultaneously. One is the classical Harpoon charge transfer mechanism determined by long-range interactions, which occurs mainly in the N2 plus (v′=1) product channel. The N2 plus ions produced by this process are concentrated in the forward scattering region and have low rotational excitation (Fig. c). The other mechanism plays a major role in the N2 plus (v′= 2) product channel. The channel products are predominantly distributed in the forward region but have high rotational excitation (Fig. d), which is inconsistent with the predictions of the classical hard-sphere collision model. Theoretical calculations show that this is a Hard collision glory scattering (HCLS) process caused by a delicate balance between the long-range attractive and short-range repulsive potentials of the two reactant molecules, which is the first time that scientists have observed a singular scattering mechanism in a charge-transfer reaction.
Това работа реализира на кинетичен проучване на сблъсък такса трансфер от квант състояние към квант състояние , и изяснява на дългогодишен противоречия в на проучване на на класически такса трансфер реакция Ar плюс плюс N2 → Ar плюс N2 плюс . The relevant research results бяха публикувани в Nature Chemistry (DOI: 10.1038/s41557-023-01278-y). Изследването работата беше подкрепено от Китайската Академия на Науки % 2c Природна Наука Фондация на Пекин и Националната Изследвания Център за Молекулярна Науки в Пекин.
ICC and others made progress in the study of charge transfer reactions with spin-orbit state selection
(a) Разсейване диаграма на продукта N2 плюс , (b) теоретично изчислено ротация квантово състояние разпределения на различни вибрационни енергийни нива на N2 плюс и корелация графики на ротация възбуждания срещу разсейване ъгли за на v′=1 (c) и v′=2 (d) вибрационно енергия нива на N2 плюс .
