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A combined time-resolved infrared and density functional theory study of the lowest excited states of 9-fluorenone and 2-naphthaldehyde
Chemical Physics ( IF 2.3 ) Pub Date : 2018-04-24 , DOI: 10.1016/j.chemphys.2018.04.014
Magnus W.D. Hanson-Heine , James A. Calladine , Jixin Yang , Michael Towrie , Raphael Horvath , Nicholas A. Besley , Michael W. George

A combined experimental and theoretical study of the infrared (IR) spectra of 2-naphthaldehyde and 9-fluorenone in their ground and first excited singlet and triplet electronic states is presented. IR studies have also been carried out using supercritical krypton (scKr) as a solvent to measure spectra in the ground and triplet excited states. This solvent provides a weakly interacting environment that is closer to the gas phase and allows a direct comparison with the calculated spectra for a single molecule. The IR spectra for the three different states are computed with Kohn-Sham density functional theory. For the first excited singlet state it is necessary to use an overlap procedure that allows the excited state to be studied by preventing variational collapse to the ground state. This allows the excited singlet state to be studied in an analogous approach to the ground and excited triplet state, in contrast to using time-dependent density functional theory. The good agreement between the calculated excited state spectra and the experiment provides insight into the nature of the excited states. For the ground and excited triplet state the anharmonic vibrational frequencies are computed using the transition optimized shifted Hermite method, and for these molecules the hybrid B97-1 functional is found to provide the closest agreement with experiment in the ground state.



中文翻译:

9-芴酮和2-萘甲醛最低激发态的时间分辨红外和密度泛函理论研究

结合实验和理论研究了2-萘醛和9-芴酮在其基态和第一个激发的单重态和三重态电子态的红外(IR)光谱。还已经使用超临界k(scKr)作为溶剂进行IR研究,以测量基态和三重激发态的光谱。该溶剂提供了一个较弱的相互作用环境,该环境更接近气相,并可以与单个分子的计算光谱直接比较。使用Kohn-Sham密度泛函理论计算了三种不同状态的IR光谱。对于第一个激发单重态,有必要使用允许激发态的重叠过程通过防止向基态的变化塌陷进行研究。与使用依赖时间的密度泛函理论相反,这允许以类似于基态和激发三重态的方法研究激发单重态。计算出的激发态光谱与实验之间的良好一致性为激发态的本质提供了见识。对于基态和激发态三重态,使用过渡优化的偏移Hermite方法计算非谐振动频率,对于这些分子,发现杂化B97-1官能团与基态的实验最接近。

更新日期:2018-07-14
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