Electronically excited states of tryptamine and its microhydrated complex

Schmitt, Michaël; Brause, Robert; Marian, Christel M.; Salzmann, Susanne; Meerts, W. Leo

doi:10.1063/1.2354494

Cited by 28 publications

(44 citation statements)

References 52 publications

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“…This is of particular importance for the analysis of protein properties using tryptophan as intrinsic sensor for the hydrophobicity of a protein pocket, as the fluorescent properties of the indole derivative tryptophan are very sensitive with regard to the polarity and proticity of the micro‐environment . In contrast to DFT/MRCI, TDDFT‐B3LYP places the more ionic and optically brighter 1 L a state erroneously below 1 L b even in apolar environments …”

Section: Performance Of the Dft/mrci Approachesmentioning

confidence: 99%

The DFT/MRCI method

Marian

Heil

Kleinschmidt

2018

WIREs Comput Mol Sci

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147

154

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In the past two decades, the combined density functional theory and multireference configuration interaction (DFT/MRCI) method has developed from a powerful approach for computing spectral properties of singlet and triplet excited states of large molecules into a more general multireference method applicable to states of all spin multiplicities. In its original formulation, it shows great efficiency in the evaluation of singlet and triplet excited states which mainly originate from local one-electron transitions. Moreover, DFT/MRCI is one of the few methods applicable to large systems that yields the correct ordering of states in extended π-systems where double excitations play a significant role. A recently redesigned DFT/MRCI Hamiltonian extends the application range of the method to bichromophores such as hydrogen-bonded or π-stacked dimers and loosely coupled donor-acceptor systems. In conjunction with a restricted-open shell Kohn-Sham optimization of the molecular orbitals, even electronically excited doublet and quartet states can be addressed. After a short outline of the general ideas behind this semi-empirical method and a brief review of alternative approaches combining density functional and multireference wavefunction theory, formulae for the DFT/MRCI Hamiltonian matrix elements are presented and the adjustments of the two-electron contributions are discussed. The performance of the DFT/MRCI variants on excitation energies of organic molecules and transition metal compounds against experimental or ab initio reference data is analyzed and case studies are presented which show the strengths and limitations of the method. Finally, an overview over the properties available from DFT/MRCI wavefunctions and further developments is given.ABBREVIATIONS: ACRXTN, 3-(9,9-dimethylacridin-10[9H]-yl)-9H-xanthen-9-one; AO, atomic orbital; CASSCF, Complete active space self-consistent field; CASPT2, Complete active space second-order perturbation theory; CCSD(T), Coupled-cluster with singles and doubles and perturbative treatment of triples; CC2, Coupled-cluster with approximate treatment of doubles; CD, Circular dichroism; CI, Configuration interaction; CIPSI, configuration interaction by perturbation with multiconfigurational zeroth-order wave functions selected by iterative

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Section: Performance Of the Dft/mrci Approachesmentioning

confidence: 99%

The DFT/MRCI method

Marian

Heil

Kleinschmidt

2018

WIREs Comput Mol Sci

Self Cite

147

154

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“…By examining the bias at which a KS energy level gets moved between the two chemical potentials of the leads (from Eq. [65] this gives a peak in the conductance), one can predict 369 positions of these peaks qualitatively, although the magnitude of the conductance may be incorrect by orders of magnitude.…”

Section: Strong Fieldsmentioning

confidence: 99%

“…49 We also see TDDFT's use in studying various fullerenes. [50][51][52][53][54][55] TDDFT is also finding many uses in biochemistry [56][57][58][59][60][61][62][63][64][65][66] where, for example, DNA bases are under examination (an overview of this area may be found in Ref. 67).…”

Section: Introductionmentioning

confidence: 99%

Excited States from Time‐Dependent Density Functional Theory

Elliott¹,

Furche²,

Burke³

2008

Reviews in Computational Chemistry

222

195

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Time-dependent density functional theory (TDDFT) is presently enjoying enormous popularity in quantum chemistry, as a useful tool for extracting electronic excited state energies. This article explains what TDDFT is, and how it differs from ground-state DFT. We show the basic formalism, and illustrate with simple examples. We discuss its implementation and possible sources of error. We discuss many of the major successes and challenges of the theory, including weak fields, strong fields, continuum states, double excitations, charge transfer, high harmonic generation, multiphoton ionization, electronic quantum control, van der Waals interactions, transport through single molecules, currents, quantum defects, and, elastic electron-atom scattering. ContentsVII. Beyond standard functionals 22 A. Double excitations 22 B. Polymers 23 C. Solids 23 D. Charge transfer 23 VIII. Other topics 23 A. Ground-state XC energy 23 B. Strong fields 24 C. Transport 25

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“…47,48 While the 1 L b state gives rise to a structured band and has a small dipole moment, the 1 L a state produces a broad band and its large dipole moment makes it sensitive to polar environment. 5,15,45 The low lying electronic excitation energies of tryptamine covers the two excited singlet pp* (L b and L a ) states. The 1 ps* has a vertical excitation of only 0.12 eV higher than that of the 1 L a state and its dipole moment is much larger than the 1 L a state.…”

Section: Lowest Excited Electronic States Of Serotoninmentioning

confidence: 99%

Spectroscopic signatures and structural motifs in isolated and hydrated serotonin: a computational study

Singh¹

2015

RSC Adv.

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The conformational landscapes of neutral serotonin and its hydrated complex were characterized by MP2, CC2 and DFT methods. The ground state geometry optimization of the twenty three lowest energy structures of serotonin have been performed employing higher basis sets. The MP2, CC2 and DFT (M06-2X, uB97X-D and B3LYP-D3) calculations predict that the Gph-out/anti conformation of serotonin is the most stable which is in agreement with the experimental rotational spectroscopy (Cabezas et al., Phys. Chem. Chem. Phys., 2012, 14, 13618) and is in contrast to the resonance-enhanced two photon ionization (R2PI) and UV-UV hole burning (UVHB) spectroscopy results. Computed wave-numbers and intensities of the observed conformers are found in consonance with the experiment (LeGreve et al., J. Am. Chem. Soc., 2007, 129, 4028). The predicted intensity of the OH bending fundamental provides a useful diagnostic for the 5-OH anti and syn conformations. The computed hydrogen bond geometries of the experimentally observed Sero 1 -(H 2 O) 1 and Sero 1 -(H 2 O) 2 clusters are found in remarkable agreement with the experiment. The Sero 1 -(H 2 O) 2 involving the Gph(out) conformation is used to form a strong water dimer bridge to the 5-OH with a binding energy of 104 kJ mol À1 . The low-lying excited states of each experimentally observed conformer of serotonin have been determined by means of coupled cluster singles and approximate doubles (CC2) and TDDFT methods and a satisfactory interpretation of the electronic absorption spectra is obtained. One striking feature is the coexistence of the blue and red shift of the vertical excitation energies of the 1 L b (pp*) and the 1 L a (pp*) state upon forming a complex with water. The effect of hydration on the lowest 1 L b (pp*) excited state due to the bulk water environment was mimicked by a combination of a polarizable continuum solvent model (PCM) and conductor like screening model (COSMO), for the different serotonin conformations which shows a red shift. The lowest excited state ( 1 L b ) of the most stable Sero 1 -(H 2 O) 1 structure shows a significant shift of 1.15Å for a water molecule towards the 5-OH group due to the S 0 -S 1 electronic excitation. † Electronic supplementary information (ESI) available: The computed structural parameters, NBO charges, rotational constants, vertical excitation energies in bulk water environment etc. of different conformers of serotonin are submitted. See

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Electronically excited states of tryptamine and its microhydrated complex

Cited by 28 publications

References 52 publications

The DFT/MRCI method

The DFT/MRCI method

Excited States from Time‐Dependent Density Functional Theory

Spectroscopic signatures and structural motifs in isolated and hydrated serotonin: a computational study

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