Solvent effect on the spectroscopic properties of indole—semiempirical quantum chemical study

Lipiński, Józef; Chojnacki, Henryk

doi:10.1016/0584-8539(94)00120-z

Cited by 10 publications

(4 citation statements)

References 41 publications

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“…The energetic position of these two states and its dependence on the polarity of solvents has been intensively studied both theoretically and experimentally. 75,77,[107][108][109] As reported previously, the L b state is the lowest state in the gas phase as well as in nonpolar solvents, while the L a state is the lowest state in polar solvents. This is due to the higher permanent dipole moment of the L a state which renders it more sensitive to the polar environment.…”

Section: A Isolated Indolesupporting

confidence: 71%

Time-dependent density functional theory excited state nonadiabatic dynamics combined with quantum mechanical/molecular mechanical approach: Photodynamics of indole in water

Wohlgemuth

Bonačić‐Koutecký

Mitrić

2011

The Journal of Chemical Physics

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We present a combination of time-dependent density functional theory with the quantum mechanical/molecular mechanical approach which can be applied to study nonadiabatic dynamical processes in molecular systems interacting with the environment. Our method is illustrated on the example of ultrafast excited state dynamics of indole in water. We compare the mechanisms of nonradiative relaxation and the electronic state lifetimes for isolated indole, indole in a sphere of classical water, and indole + 3H(2)O embedded in a classical water sphere. In the case of isolated indole, the initial excitation to the S(2) electronic state is followed by an ultrafast internal conversion to the S(1) state with a time constant of 17 fs. The S(1) state is long living (>30 ps) and deactivates to the ground state along the N-H stretching coordinate. This deactivation mechanism remains unchanged for indole in a classical water sphere. However, the lifetimes of the S(2) and S(1) electronic states are extended. The inclusion of three explicit water molecules opens a new relaxation channel which involves the electron transfer to the solvent, leading eventually to the formation of a solvated electron. The relaxation to the ground state takes place on a time scale of 60 fs and contributes to the lowering of the fluorescence quantum yield. Our simulations demonstrate the importance of including explicit water molecules in the theoretical treatment of solvated systems.

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Section: A Isolated Indolesupporting

confidence: 71%

Time-dependent density functional theory excited state nonadiabatic dynamics combined with quantum mechanical/molecular mechanical approach: Photodynamics of indole in water

Wohlgemuth

Bonačić‐Koutecký

Mitrić

2011

The Journal of Chemical Physics

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“…The transition dipole moment of Toac, lying in the CNC plane,12 was taken perpendicular to the NO bond, while the transition dipole moment of Trp was chosen to be 1 L a ,45 because by using 1 L b the computed κ

_{2}^{italicm}

parameter leads to a very poor agreement between calculated and observed efficiency. This finding is consistent with recent theoretical and experimental data,46, 47 indicating that in polar solvent media, such as methanol, the emitting state is 1 L a . Finally, the angle that the Trp transition dipole moment makes with the line joining the center of mass of Trp and Toac is denoted as γ, while E is the vector representing the electric field at the center of mass of Toac induced by the transition dipole moment of Trp, and θ the angle between E and the transition dipole moment of Toac.…”

Section: Resultssupporting

confidence: 93%

A spectroscopic and molecular mechanics investigation on a series of AIB-based linear peptides and a peptide template, both containing tryptophan and a nitroxide derivative as probes

et al. 2000

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“…Except for the frozen‐core approximation, the ZINDO/S‐CIS calculations have been carried out without any restriction on the orbital active space. The Mataga and Nishimoto parametrization 71 for spectroscopy is used in the INDO/1 72 method. Dynamic electron correlation is partially accounted for by the rather powerful combination with the CIS 73 scheme for singly excited particle–hole states.…”

Section: Theory and Computational Detailsmentioning

confidence: 99%

Temperature effects on the UV–Vis electronic spectrum of trans‐stilbene

Kwasniewski¹,

François²,

Deleuze³

2001

Int J of Quantum Chemistry

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ABSTRACT:The ultraviolet (UV)-Visible absorption spectrum of trans-stilbene (tS) is computed at different temperatures by couplin g molecular dynamic s (MD ) simulations with the classical MM 3 force fiel d to ZINDO/S-CI S calculation s of vertical excitation energies and transition dipol e moments. The selection of a large number of structures along the MDtrajectories enables a consistent treatment of temperature effects in the vacuum , whereas the ZINDO/S-CI S calculation s permit a reliable treatment of electron correlation and relaxation, taking account of multistat e interactions in the fina l state. Thermal motions are found to alter very differentl ythe width and shape of bands. Structural alterations such as the stretching and the torsion of the vinyl single and double bonds very stronglyinfluenc e the appearance of the fi rst valence state, pertaining to the highest occupied and lowest unoccupied molecular orbital (HOMO-LUMO ) transition. At temperatures less than 400 K, these are found to yield a merelyGaussian and very pronounce d thermal broadenin g of the related band (A), up to nearly 30 nm, together with a minor blue shift of its maximum λ max . In contrast, a red shift by several nanometers occurs due to thermal motions for the remainin g three valence bands. As can be expected, the broadenin g intensifie s at higher temperatures, and for the A-band , becomes markedly asymmetric when T exceeds 400 K. The combinatio n of MD(MM3 ) and ZINDO/S-CIS computation s enables also consistent calculation s of hot bands, which are forbidden by symmetryat 0 K.

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Solvent effect on the spectroscopic properties of indole—semiempirical quantum chemical study

Cited by 10 publications

References 41 publications

Time-dependent density functional theory excited state nonadiabatic dynamics combined with quantum mechanical/molecular mechanical approach: Photodynamics of indole in water

Time-dependent density functional theory excited state nonadiabatic dynamics combined with quantum mechanical/molecular mechanical approach: Photodynamics of indole in water

A spectroscopic and molecular mechanics investigation on a series of AIB-based linear peptides and a peptide template, both containing tryptophan and a nitroxide derivative as probes

Temperature effects on the UV–Vis electronic spectrum of trans‐stilbene

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