The dynamics of OH channel in the 266 and 355nm photodissociation of 2-nitrophenol

Wei, Qiang; Yin, Hongming; Sun, Julong; Yue, Xian-Fang; Han, Keli

doi:10.1016/j.cplett.2008.08.080

Cited by 17 publications

(27 citation statements)

References 23 publications

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“…By using ab initio quantum chemistry method at 6SA-CASSCF(10, 10)/6-31G (d, p) and MRCI/cc-pVDZ level, we previously optimized geometries for all isomers and transition states on two low-lying singlet (S 0 and S 1 ) and two low-lying triplet (T 1 and T 2 ) electronic states and we computed all four-state potential energy profiles along ESIPT coordinates 30 . We confirmed the existence of unstable aci-nitrophenol isomers as observed in the early studies 23 24 29 30 . We found total five ISC zones with SOCs at ~10 and ~40 wavenumbers.…”

supporting

confidence: 88%

“…Differing from the other aromatic systems, the experimental and theoretical studies demonstrate peculiar behavior of the photoinduced decay process for nitrated aromatic compounds. The tautomeric aci-nitrophenol isomers via photoisomerization has been confirmed by infrared spectroscopy in low-temperature argon matrices 23 and by laser-induced-fluorescence 24 . The rich intersystem crossing network makes o -nitrophenol from the first excited singlet state decaying to the triplet states rapidly, and the process occurs in the femtoseconds to a few picoseconds time scale dependent on the intermediate states 25 26 27 .…”

mentioning

confidence: 79%

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Intersystem crossing-branched excited-state intramolecular proton transfer for o-nitrophenol: An ab initio on-the-fly nonadiabatic molecular dynamic simulation

Zhu³

et al. 2016

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The 6SA-CASSCF(10, 10)/6-31G (d, p) quantum chemistry method has been applied to perform on-the-fly trajectory surface hopping simulation with global switching algorithm and to explore excited-state intramolecular proton transfer reactions for the o-nitrophenol molecule within low-lying electronic singlet states (S0 and S1) and triplet states (T1 and T2). The decisive photoisomerization mechanisms of o-nitrophenol upon S1 excitation are found by three intersystem crossings and one conical intersection between two triplet states, in which T1 state plays an essential role. The present simulation shows branch ratios and timescales of three key processes via T1 state, non-hydrogen transfer with ratio 48% and timescale 300 fs, the tunneling hydrogen transfer with ratios 36% and timescale 10 ps, and the direct hydrogen transfer with ratios 13% and timescale 40 fs. The present simulated timescales might be close to low limit of the recent experiment results.

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supporting

confidence: 88%

mentioning

confidence: 79%

Intersystem crossing-branched excited-state intramolecular proton transfer for o-nitrophenol: An ab initio on-the-fly nonadiabatic molecular dynamic simulation

Zhu³

et al. 2016

Sci Rep

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“…OH was observed to be formed cold (ν = 0) with a rotational energy of only 8 ± 0.8 kJ mol –1 . Earlier work by Wei et al in the same research group found similar results at 266 and 355 nm. These observations are fully compatible with the OH + nitrosophenoxy energy predicted theoretically at 302 kJ mol –1 .…”

Section: Comparison To Experimentssupporting

confidence: 73%

“…Nitrophenol and aci‐nitrophenol exist both as singlet and triplet compounds. Labeling of the aci‐nitrophenol compounds follows Wei et al . The depicted Lewis structures show but one of many resonance structures.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study on the Formation of H- and O-Atoms, HONO, OH, NO, and NO₂from the Lowest Lying Singlet and Triplet States inOrtho-Nitrophenol Photolysis

Vereecken

Chakravarty

Bohn

et al. 2016

Int. J. Chem. Kinet.

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The photolysis of nitrophenols was proposed as a source of reactive radicals and NOx compounds in polluted air. The S0 singlet ground state and T1 first excited triplet state of nitrophenol were investigated to assess the energy dependence of the photofragmentation product distribution as a function of the reaction conditions, based on quantum chemical calculations at the G3SX//M06–2X/aug‐cc‐pVTZ level of theory combined with RRKM master equation calculations. On both potential energy surfaces, we find rapid isomerization with the aci‐nitrophenol isomer, as well as pathways forming NO, NO2, OH, HONO, and H‐, and O‐atoms, extending earlier studies on the T1 state and in agreement with available work on other nitroaromatics. We find that accessing the lowest photofragmentation channel from the S0 ground state requires only 268 kJ/mol of activation energy, but at a pressure of 1 atm collisional energy loss dominates such that significant fragmentation only occurs at internal energies exceeding 550 kJ/mol, making this surface unimportant for atmospheric photolysis. Intersystem crossing to the T1 triplet state leads more readily to fragmentation, with dissociation occurring at energies of ∼450 kJ/mol above the singlet ground state even at 1 atm. The main product is found to be OH + nitrosophenoxy, followed by formation of hydroxyphenoxy + NO and phenyloxyl + HONO. The predictions are compared against available experimental data.

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“…Nitroarenes are directly emitted into the atmosphere or can be formed in situ by secondary photochemical processes in the atmosphere. [7] Recent work on different aspects of aromatic hydrocarbon photooxidation processes performed in the presence of OH-radical scavengers revealed that OH radicals are generated during the photolysis of nitrophenols, [8] and the hydroxyl radical has also been directly observed in the photodissociation of o-nitrophenol [9] and nitro-A C H T U N G T R E N N U N G toluene. [10] Among various nitroarenes, o-nitrobenzaldehyde (o-NBA) has been studied extensively for more than 100 years because of its high photosensitivity, though research has mainly focused on its photochemistry in solution.…”

Section: Introductionmentioning

confidence: 99%

Photolysis of o‐Nitrobenzaldehyde in the Gas Phase: A New OH^. Formation Channel

et al. 2009

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Photolysis of gaseous o-nitrobenzaldehyde (o-NBA) with selected different excitation wavelengths (355-400 nm) is investigated, and the nascent OH radical is detected by the single-photon laser-induced fluorescence (LIF) technique. The relative quantum yield and rotational excitation of OH formation are found to be dependent on the excitation energy. The distributions of rotational, spin-orbit, and Lambda-doublet states are obtained at 355-400 nm by analyzing the experimental data. The OH radicals are found to be vibrationally cold at all photolysis wavelengths. The spin-orbit and Lambda-doublet states have nonstatistical distributions. To understand the dissociative process involved in the OH-generating channel, DFT calculations are performed. Based on both experimental and theoretical results, possible photolysis channels of o-NBA leading to the OH fragment are proposed and discussed.

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The dynamics of OH channel in the 266 and 355nm photodissociation of 2-nitrophenol

Cited by 17 publications

References 23 publications

Intersystem crossing-branched excited-state intramolecular proton transfer for o-nitrophenol: An ab initio on-the-fly nonadiabatic molecular dynamic simulation

Intersystem crossing-branched excited-state intramolecular proton transfer for o-nitrophenol: An ab initio on-the-fly nonadiabatic molecular dynamic simulation

Theoretical Study on the Formation of H- and O-Atoms, HONO, OH, NO, and NO₂from the Lowest Lying Singlet and Triplet States inOrtho-Nitrophenol Photolysis

Photolysis of o‐Nitrobenzaldehyde in the Gas Phase: A New OH^. Formation Channel

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The dynamics of OH channel in the 266 and 355nm photodissociation of 2-nitrophenol

Cited by 17 publications

References 23 publications

Intersystem crossing-branched excited-state intramolecular proton transfer for o-nitrophenol: An ab initio on-the-fly nonadiabatic molecular dynamic simulation

Intersystem crossing-branched excited-state intramolecular proton transfer for o-nitrophenol: An ab initio on-the-fly nonadiabatic molecular dynamic simulation

Theoretical Study on the Formation of H- and O-Atoms, HONO, OH, NO, and NO2from the Lowest Lying Singlet and Triplet States inOrtho-Nitrophenol Photolysis

Photolysis of o‐Nitrobenzaldehyde in the Gas Phase: A New OH. Formation Channel

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Product

Resources

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Theoretical Study on the Formation of H- and O-Atoms, HONO, OH, NO, and NO₂from the Lowest Lying Singlet and Triplet States inOrtho-Nitrophenol Photolysis

Photolysis of o‐Nitrobenzaldehyde in the Gas Phase: A New OH^. Formation Channel