Kim Jinwoo, Kim Junggil, Kim Sang Kyu
Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea.
J Phys Chem A. 2025 Jan 9;129(1):174-179. doi: 10.1021/acs.jpca.4c07507. Epub 2024 Dec 27.
A photodetachment and photoelectron spectroscopic study by employing a cryogenically cooled ion trap combined with a velocity-map imaging setup has been carried out to unravel the vibrational structures and autodetachment dynamics of the dipole-bound states (DBSs) of -, -, and -methylphenolate anions (-, -, and -CHPhO). The electron binding energy of the DBS increases monotonically with the increase of the neutral dipole moment to give respective values of 66 ± 15, 123 ± 18, or 154 ± 14 cm for the -, -, or -isomer. The different electron-donating effects of the methyl moieties in the three geometrically different isomers seem to be reflected in the experiment. Mode-specific DBS dynamics of the -, -, and -CHPhO complexes have been interrogated by using picosecond time-resolved photoelectron velocity-map imaging spectroscopy. Autodetachment lifetimes of the DBS vibrational Feshbach resonances have been measured and discussed quantitatively using Fermi's golden rule, especially in comparison with those of the phenoxide anion to get insights into the methyl substitution effect on the electron binding dynamics of the metastable DBS.
通过采用低温冷却离子阱与速度成像装置相结合的方法进行了光剥离和光电子能谱研究，以揭示邻、间、对甲基苯酚根阴离子（邻-CHPhO、间-CHPhO、对-CHPhO）的偶极束缚态（DBSs）的振动结构和自剥离动力学。DBS的电子结合能随着中性偶极矩的增加而单调增加，邻、间、对异构体的电子结合能分别为66±15、123±18或154±14cm⁻¹。实验似乎反映出了三种几何异构体中甲基部分不同的给电子效应。利用皮秒时间分辨光电子速度成像光谱研究了邻-CHPhO、间-CHPhO和对-CHPhO配合物的特定模式DBS动力学。测量了DBS振动费什巴赫共振的自剥离寿命，并使用费米黄金规则进行了定量讨论，特别是与苯氧根阴离子的自剥离寿命进行比较，以深入了解甲基取代对亚稳DBS电子结合动力学的影响。
