Abstract:Here, we employ the CASPT2//CASSCF and QM(CASPT2//CASSCF)/MM approaches to explore the photochemical mechanism of homomenthyl salicylate (HMS) in vacuum and an acetonitrile solution. The results show that in both cases, the excited-state relaxation mainly involves a spectroscopically "bright" S 1 ( 1 ππ*) state and the lower-lying T 1 and T 2 states. In the major relaxation pathway, the photoexcited S 1 keto system first undergoes an essentially barrierless excited-state intramolecular proton transfer (ESIPT) … Show more
“…[63][64][65] The final MD snapshot that deletes the frozen methanol molecules is utilized as the starting structure for the following QM/MM calculations and this strategy has been used in many similar works before. [35][36][37][66][67][68][69][70] Fig. 1 shows our used QM/MM model.…”
Section: System Setupmentioning
confidence: 99%
“…75,76 The 6-31G* basis set [77][78][79] is employed for all the computations, which has been utilized in many similar works and has been demonstrated to provide accurate description of excited-state structures and energetics. [30][31][32][33][34][35][36][37][45][46][47][48] Vertical excitation energies and dipole moments at the Franck-Condon point and spin-orbit coupling matrix elements with the atomic mean-field approximation are calculated at the QM(CASPT2)/MM level. [80][81][82] All QM/MM calculations are carried out using the MOLCAS8.0 package interfaced with the TINKER6.3.2 package.…”
Section: Qm and Qm/mm Calculationsmentioning
confidence: 99%
“…[83][84][85][86][87] This QM/MM approach was recently shown to provide an accurate description for excited-state structures and energetics in organic and protein systems. [35][36][37][66][67][68][69][70] Results and discussion S 0 minima and vertical excitation energies At the QM(CASSCF)/MM level, we optimize the S 0 equilibrium structures for the normal and proton transfer tautomers, which are denoted as S0-ENOL and S0-KETO, respectively, in Fig. 3.…”
Section: Qm and Qm/mm Calculationsmentioning
confidence: 99%
“…This barrierless ground-state reverse process has also been found in previous works, for example in salicylic acid, methyl salicylate, GFP chromophores, indigo, etc. [36][37][38][45][46][47][48][49][88][89][90][91][92][93]…”
Section: Excited-state Minima and Proton Transfer Pathsmentioning
confidence: 99%
“…Also, note that a similar singletmediated ESIPT mechanism is also widely found in many similar compounds such as in salicylic acid, homosalate, GFP Chromophore, indigo etc. [36][37][38][45][46][47][48][49][88][89][90][91][92] The minor ones are related the ISC processes. At S2-PP-ENOL, the existence of the S 2 ( 1 pp*)/S 1 ( 1 np*)/T 2 ( 3 np*) three-state intersection region helps the S 2 system hop to the S 1 and T 2 state via S 2 -S 1 IC and S 2 -T 2 ISC (spin-orbit coupling: 5.8 cm À1 ) processes.…”
Herein we have employed the QM(CASPT2//CASSCF)/MM method to explore the photophysical and photochemical mechanism of oxybenzone (OB) in methanol solution. Based on the optimized minima, conical intersections and crossing points,...
“…[63][64][65] The final MD snapshot that deletes the frozen methanol molecules is utilized as the starting structure for the following QM/MM calculations and this strategy has been used in many similar works before. [35][36][37][66][67][68][69][70] Fig. 1 shows our used QM/MM model.…”
Section: System Setupmentioning
confidence: 99%
“…75,76 The 6-31G* basis set [77][78][79] is employed for all the computations, which has been utilized in many similar works and has been demonstrated to provide accurate description of excited-state structures and energetics. [30][31][32][33][34][35][36][37][45][46][47][48] Vertical excitation energies and dipole moments at the Franck-Condon point and spin-orbit coupling matrix elements with the atomic mean-field approximation are calculated at the QM(CASPT2)/MM level. [80][81][82] All QM/MM calculations are carried out using the MOLCAS8.0 package interfaced with the TINKER6.3.2 package.…”
Section: Qm and Qm/mm Calculationsmentioning
confidence: 99%
“…[83][84][85][86][87] This QM/MM approach was recently shown to provide an accurate description for excited-state structures and energetics in organic and protein systems. [35][36][37][66][67][68][69][70] Results and discussion S 0 minima and vertical excitation energies At the QM(CASSCF)/MM level, we optimize the S 0 equilibrium structures for the normal and proton transfer tautomers, which are denoted as S0-ENOL and S0-KETO, respectively, in Fig. 3.…”
Section: Qm and Qm/mm Calculationsmentioning
confidence: 99%
“…This barrierless ground-state reverse process has also been found in previous works, for example in salicylic acid, methyl salicylate, GFP chromophores, indigo, etc. [36][37][38][45][46][47][48][49][88][89][90][91][92][93]…”
Section: Excited-state Minima and Proton Transfer Pathsmentioning
confidence: 99%
“…Also, note that a similar singletmediated ESIPT mechanism is also widely found in many similar compounds such as in salicylic acid, homosalate, GFP Chromophore, indigo etc. [36][37][38][45][46][47][48][49][88][89][90][91][92] The minor ones are related the ISC processes. At S2-PP-ENOL, the existence of the S 2 ( 1 pp*)/S 1 ( 1 np*)/T 2 ( 3 np*) three-state intersection region helps the S 2 system hop to the S 1 and T 2 state via S 2 -S 1 IC and S 2 -T 2 ISC (spin-orbit coupling: 5.8 cm À1 ) processes.…”
Herein we have employed the QM(CASPT2//CASSCF)/MM method to explore the photophysical and photochemical mechanism of oxybenzone (OB) in methanol solution. Based on the optimized minima, conical intersections and crossing points,...
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