The Excited State Absorption Kinetics of Quinoxaline in Room Temperature Solution

Single-molecule detection is a powerful method used to distinguish different species and follow time trajectories within the ensemble average. However, such detection capability requires efficient emitters and is prone to photobleaching, and the slow, nanosecond spontaneous emission process only reports on the lowest excited state. We demonstrate direct detection of stimulated emission from individual colloidal nanocrystals at room temperature while simultaneously recording the depleted spontaneous emission, enabling us to trace the carrier population through the entire photocycle. By capturing the femtosecond evolution of the stimulated emission signal, together with the nanosecond fluorescence, we can disentangle the ultrafast charge trajectories in the excited state and determine the populations that experience stimulated emission, spontaneous emission, and excited-state absorption processes.

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Role of Electronic Excited State in Kinetics of the CH2OO + SO2 ! HCHO + SO3 Reaction

10.26434/chemrxiv.14183039 ◽

2021 ◽

Author(s):

Qingfei Song ◽

Qiuyu Zhang ◽

Qingyong Meng

Keyword(s):

Excited State ◽

Room Temperature ◽

Energy Surface ◽

Regression Method ◽

Vibrationally Excited ◽

Compute Data ◽

Ring Polymer ◽

Experimental Values ◽

Kinetics Of

In this work, kinetics of the CH2OO + SO2 ! HCHO + SO3 reaction was studied by ring-polymer molecular dynamics (RPMD). To perform RPMD calculations, multi-reference configuration interaction (MRCI) was first carried out to compute data for constructing potential energy surface (PES) through a kernel regression method. On the basis of the present MRCI calculations, the statics multi-state mechanism involving the lowest-lying singlet excited state (denoted by S 1) was proposed, which is di?erent from the previously proposed mechanism with the lowest-lying triplet state (denoted by T1). Moreover, the present RPMD calculations predicted the rate coe?cient of 3:95?10􀀀11cm3 molecule􀀀1s􀀀1 at the room temperature (namely 298 K), agreeing with the previously reported experimental values. Finally, based on the present calculations, a probable dynamics mechanism was discussed, where the produced HCHO molecule was proposed to be in a vibrationally excited state. This needs further experimental and theoretical observation in the future.<br>

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Role of Electronic Excited State in Kinetics of the CH2OO + SO2 ! HCHO + SO3 Reaction

10.26434/chemrxiv.14183039.v1 ◽

2021 ◽

Author(s):

Qingfei Song ◽

Qiuyu Zhang ◽

Qingyong Meng

Keyword(s):

Excited State ◽

Room Temperature ◽

Energy Surface ◽

Regression Method ◽

Vibrationally Excited ◽

Compute Data ◽

Ring Polymer ◽

Experimental Values ◽

Kinetics Of

In this work, kinetics of the CH2OO + SO2 ! HCHO + SO3 reaction was studied by ring-polymer molecular dynamics (RPMD). To perform RPMD calculations, multi-reference configuration interaction (MRCI) was first carried out to compute data for constructing potential energy surface (PES) through a kernel regression method. On the basis of the present MRCI calculations, the statics multi-state mechanism involving the lowest-lying singlet excited state (denoted by S 1) was proposed, which is di?erent from the previously proposed mechanism with the lowest-lying triplet state (denoted by T1). Moreover, the present RPMD calculations predicted the rate coe?cient of 3:95?10􀀀11cm3 molecule􀀀1s􀀀1 at the room temperature (namely 298 K), agreeing with the previously reported experimental values. Finally, based on the present calculations, a probable dynamics mechanism was discussed, where the produced HCHO molecule was proposed to be in a vibrationally excited state. This needs further experimental and theoretical observation in the future.<br>

Download Full-text