Density Functional Methods for Excited States: Equilibrium Structure and Electronic Spectra

Furche, Filipp; Rappoport, Dmitrij

doi:10.1016/s1380-7323(05)80020-2

Cited by 261 publications

(253 citation statements)

References 355 publications

(268 reference statements)

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“…The use of solvent in the calculation of the excited states is needed in depicting the real environment of the analogues which can give a much better agreement with the experimental values; on the other hand, calculating the analogues in the gas phase, could give reversed oscillator strengths on its transition energies giving an error in its simulated spectra as observed with some porphyrins with fused benzoheterocycles. 55 This also confirms the statement of Furche and Rapport 56 that the use of 6-31G* as the basis set to calculate excitation energies is sufficient for planar systems. This greatly decreases the computational time compared with using the more expensive triple-or quadruple-z basis sets.…”

Section: Resultssupporting

confidence: 74%

DFT/TD-DFT molecular design of porphyrin analogues for use in dye-sensitized solar cells

Balanay

Kim

2008

Phys. Chem. Chem. Phys.

139

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Density functional theory (DFT) and time-dependent DFT calculations have been employed to model Zn meso-tetraphenylporphyrin (ZnTPP) complexes having different b-substituents, in order to design an efficient sensitizer for dye-sensitized solar cells. To calculate the excited states of the porphyrin analogues, at least the TD-B3LYP/6-31G* level of theory is needed to replicate the experimental absorption spectra. Solvation results were found to be invariant with respect to the type of model used (PCM vs. C-PCM). Most of the electronic transitions based on Gouterman's four-orbital model of ZnTPP-A and ZnTPP-B are p -p* transitions, so that cell efficiency can be enhanced by increasing the p-conjugation and electron-withdrawing capability of the bsubstituent. This proposition was tested by inserting thiophene into the b-substituent of ZnTPP-A to form a new analogue, ZnTPP-C. Compared with ZnTPP-A and ZnTPP-B, ZnTPP-C has a smaller band gap, which brings LUMO closer to the conduction band of TiO 2 , and a red-shifted absorption spectrum with higher extinction coefficients, especially in the Q-band position.

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Section: Resultssupporting

confidence: 74%

DFT/TD-DFT molecular design of porphyrin analogues for use in dye-sensitized solar cells

Balanay

Kim

2008

Phys. Chem. Chem. Phys.

139

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“…The popular linear-response time-dependent DFT (TDDFT) method provides accurate excitation energies at a much lower cost than ab initio correlation calculations. [11][12][13] However, a number of problematic cases exists, where today's functionals are not able to provide accurate excitation energies. 2,5,[14][15][16][17][18] Thus, alternative methods to assess the accuracy of the TDDFT calculations on large molecules are needed.…”

Section: Introductionmentioning

confidence: 99%

Reduction of the virtual space for coupled-cluster excitation energies of large molecules and embedded systems

Send¹,

Kaila²,

Sundholm³

2011

The Journal of Chemical Physics

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We investigate how the reduction of the virtual space affects coupled-cluster excitation energies at the approximate singles and doubles coupled-cluster level (CC2). In this reduced-virtual-space (RVS) approach, all virtual orbitals above a certain energy threshold are omitted in the correlation calculation. The effects of the RVS approach are assessed by calculations on the two lowest excitation energies of 11 biochromophores using different sizes of the virtual space. Our set of biochromophores consists of common model systems for the chromophores of the photoactive yellow protein, the green fluorescent protein, and rhodopsin. The RVS calculations show that most of the high-lying virtual orbitals can be neglected without significantly affecting the accuracy of the obtained excitation energies. Omitting all virtual orbitals above 50 eV in the correlation calculation introduces errors in the excitation energies that are smaller than 0.1 eV. By using a RVS energy threshold of 50 eV, the CC2 calculations using triple-ζ basis sets (TZVP) on protonated Schiff base retinal are accelerated by a factor of 6. We demonstrate the applicability of the RVS approach by performing CC2/TZVP calculations on the lowest singlet excitation energy of a rhodopsin model consisting of 165 atoms using RVS thresholds between 20 eV and 120 eV. The calculations on the rhodopsin model show that the RVS errors determined in the gas-phase are a very good approximation to the RVS errors in the protein environment. The RVS approach thus renders purely quantum mechanical treatments of chromophores in protein environments feasible and offers an ab initio alternative to quantum mechanics/molecular mechanics separation schemes.

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“…Analytical gradient techniques make computation of geometric derivatives particularly efficient in the framework of time-dependent density functional theory (TDDFT). 32 In addition, the sum-over-states approach may be used to identify major contributions to resonance Raman intensities. We apply the present approach to assign and interpret resonance Raman scattering in nucleic acid bases.…”

mentioning

confidence: 99%

“…In this limit, the shape of the resonance Raman spectrum reflects the structure of the potential energy surface of the excited state k. Since the A term is quadratic in the resonance Analytical derivative techniques allow to compute excitation energy gradients and non-resonant polarizability derivatives in an efficient fashion using TDDFT. 32,36 In this work, derivatives of transition dipole moments are computed by numerical differentiation. However, an analytical implementation is possible starting from a Lagrangian formulation, 37 similar to that for gradients of excitation energies 38,39 and frequency-dependent polarizabilities.…”

mentioning

confidence: 99%

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Simplified Sum-Over-States Approach for Predicting Resonance Raman Spectra. Application to Nucleic Acid Bases

Rappoport

Shim

Aspuru‐Guzik

2011

J. Phys. Chem. Lett.

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Resonance Raman spectra provide a valuable probe into molecular excited-state structures and properties. Moreover, resonance enhancement is of importance for the chemical contribution to surface-enhanced Raman scattering. In this work, we introduce a simplified sum-over-states scheme for computing Raman spectra and Raman excitation profiles. The proposed sum-over-states approach uses derivatives of electronic excitation energies and transition dipole moments, which can be efficiently computed from time-dependent density functional theory. We analyze and interpret the resonance Raman spectra and Raman excitation profiles of nucleic acid bases using the present approach. Contributions of individual excited states under strictly resonant and nonresonant conditions are investigated, and smooth interpolation between both limiting cases is obtained.

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Density Functional Methods for Excited States: Equilibrium Structure and Electronic Spectra

Cited by 261 publications

References 355 publications

DFT/TD-DFT molecular design of porphyrin analogues for use in dye-sensitized solar cells

DFT/TD-DFT molecular design of porphyrin analogues for use in dye-sensitized solar cells

Reduction of the virtual space for coupled-cluster excitation energies of large molecules and embedded systems

Simplified Sum-Over-States Approach for Predicting Resonance Raman Spectra. Application to Nucleic Acid Bases

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