Details
| Original language | English |
|---|---|
| Pages (from-to) | 1177-1182 |
| Number of pages | 6 |
| Journal | ChemPhysChem |
| Volume | 4 |
| Issue number | 11 |
| Early online date | 6 Nov 2003 |
| Publication status | Published - 14 Nov 2003 |
| Externally published | Yes |
Abstract
We present a hybrid Car-Parrinello quantum mechanical/molecular mechanical (QM/MM) approach that is capable of treating the dynamics of molecular systems in electronically excited states in complex environments. The potential energy surface in the excited state is described either within the restricted open-shell Kohn-Sham (ROKS) formalism or within time-dependent density functional theory (TDDFT). As a test case, we apply this technique to the study of the solvent effects on the ground state and on the first excited singlet state of acetone in water. Our results demonstrate that for this system a purely classical description of the solvent is sufficient, since inclusion of the first solvent shell of 12 water molecules into the quantum system does not show a significant effect on this transition. The excited-state energies calculated with ROKS are red shifted by a constant value compared to the TDDFT results, while the relative variations of the excitation energy for different configurations are in very good agreement. The experimentally observed blue shift of the excitation energy in going from gas phase to condensed phase is well reproduced. Excited-state dynamics carried out with ROKS yield the relaxation of the solute and the rearrangement of the solvent structure on a picosecond timescale. The calculated Stokes shift is in reasonable agreement with experimental data.
Keywords
- Absorption, Density functional calculations, Fluorescence, Molecular dynamics, Solvent effects
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Atomic and Molecular Physics, and Optics
- Chemistry(all)
- Physical and Theoretical Chemistry
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In: ChemPhysChem, Vol. 4, No. 11, 14.11.2003, p. 1177-1182.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - QM/MM Car-Parrinello Molecular Dynamics Study of the Solvent Effects on the Ground State and on the First Excited Singlet State of Acetone in Water
AU - Röhrig, Ute F.
AU - Frank, Irmgard
AU - Hutter, Jürg
AU - Laio, Alessandro
AU - VandeVondele, Joost
AU - Rothlisberger, Ursula
PY - 2003/11/14
Y1 - 2003/11/14
N2 - We present a hybrid Car-Parrinello quantum mechanical/molecular mechanical (QM/MM) approach that is capable of treating the dynamics of molecular systems in electronically excited states in complex environments. The potential energy surface in the excited state is described either within the restricted open-shell Kohn-Sham (ROKS) formalism or within time-dependent density functional theory (TDDFT). As a test case, we apply this technique to the study of the solvent effects on the ground state and on the first excited singlet state of acetone in water. Our results demonstrate that for this system a purely classical description of the solvent is sufficient, since inclusion of the first solvent shell of 12 water molecules into the quantum system does not show a significant effect on this transition. The excited-state energies calculated with ROKS are red shifted by a constant value compared to the TDDFT results, while the relative variations of the excitation energy for different configurations are in very good agreement. The experimentally observed blue shift of the excitation energy in going from gas phase to condensed phase is well reproduced. Excited-state dynamics carried out with ROKS yield the relaxation of the solute and the rearrangement of the solvent structure on a picosecond timescale. The calculated Stokes shift is in reasonable agreement with experimental data.
AB - We present a hybrid Car-Parrinello quantum mechanical/molecular mechanical (QM/MM) approach that is capable of treating the dynamics of molecular systems in electronically excited states in complex environments. The potential energy surface in the excited state is described either within the restricted open-shell Kohn-Sham (ROKS) formalism or within time-dependent density functional theory (TDDFT). As a test case, we apply this technique to the study of the solvent effects on the ground state and on the first excited singlet state of acetone in water. Our results demonstrate that for this system a purely classical description of the solvent is sufficient, since inclusion of the first solvent shell of 12 water molecules into the quantum system does not show a significant effect on this transition. The excited-state energies calculated with ROKS are red shifted by a constant value compared to the TDDFT results, while the relative variations of the excitation energy for different configurations are in very good agreement. The experimentally observed blue shift of the excitation energy in going from gas phase to condensed phase is well reproduced. Excited-state dynamics carried out with ROKS yield the relaxation of the solute and the rearrangement of the solvent structure on a picosecond timescale. The calculated Stokes shift is in reasonable agreement with experimental data.
KW - Absorption
KW - Density functional calculations
KW - Fluorescence
KW - Molecular dynamics
KW - Solvent effects
UR - http://www.scopus.com/inward/record.url?scp=0345276570&partnerID=8YFLogxK
U2 - 10.1002/cphc.200300650
DO - 10.1002/cphc.200300650
M3 - Article
AN - SCOPUS:0345276570
VL - 4
SP - 1177
EP - 1182
JO - ChemPhysChem
JF - ChemPhysChem
SN - 1439-4235
IS - 11
ER -