Calculation of Vibrational Resonance
            <scp>R</scp>
            aman Spectra of Molecules Using Quantum Chemistry Methods

Guthmuller, Julien

doi:10.1002/9783527814596.ch17

Cited by 9 publications

(14 citation statements)

References 162 publications

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“…When compared against the off-resonance Raman spectra in Figure 6, the RR spectra in Figure 8 immediately show evidence of selective resonance enhancement, as is characteristic of RR spectroscopy [86][87][88]. That is particularly evidenced by the slight changes in the position and strong changes in the intensity of some of the peaks described above.…”

Section: Resonance Ramanmentioning

confidence: 75%

Ring Vibrations to Sense Anionic Ibuprofen in Aqueous Solution as Revealed by Resonance Raman

et al. 2022

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We unravel the potentialities of resonance Raman spectroscopy to detect ibuprofen in diluted aqueous solutions. In particular, we exploit a fully polarizable quantum mechanics/molecular mechanics (QM/MM) methodology based on fluctuating charges coupled to molecular dynamics (MD) in order to take into account the dynamical aspects of the solvation phenomenon. Our findings, which are discussed in light of a natural bond orbital (NBO) analysis, reveal that a selective enhancement of the Raman signal due to the normal mode associated with the C–C stretching in the ring, νC=C, can be achieved by properly tuning the incident wavelength, thus facilitating the recognition of ibuprofen in water samples.

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Section: Resonance Ramanmentioning

confidence: 75%

Ring Vibrations to Sense Anionic Ibuprofen in Aqueous Solution as Revealed by Resonance Raman

et al. 2022

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“…Within the IMDHO picture, the quantities Δ j and Δ k are the displacements (between initial and final electronic states) of the minimum-energy geometry along the modes Q j and Q k . As in a previous work, these can be computed from the gradient ∂Ω/∂ Q of the electronic transition energy, Ω: Note that Δ k is a signed quantity that carries information regarding the equilibrium position of the upper state with respect to the lower state . For resonant enhancement using the S 1 → S 2 transition, the calculation of ∂Ω/∂ Q k requires two TD-DFT gradient calculations at each time step, one for the S 1 state and one for S 2 .…”

Section: Resultsmentioning

confidence: 99%

“…For FSRS experiments that probe dynamics through a conical intersection, nonadiabatic ai MD algorithms will be required, − for example, based on trajectory surface hopping. , The ab initio nature of the present approach to FSRS should be integrable with these nonadiabatic ai MD algorithms. For reactive FSRS, experiments have emphasized the role of anharmonic couplings, for which the excited-state gradient formalism that is used herein to compute RR intensity enhancements would need to be replaced by a more general formalism based on derivatives of the polarizability tensor . This might also be helpful for resolving experimental ambiguities regarding signals arising from lower-order nonlinear processes, which complicate the analysis of FSRS spectra .…”

Section: Discussionmentioning

confidence: 99%

“…For reactive FSRS, experiments have emphasized the role of anharmonic couplings, 42 for which the excited-state gradient formalism that is used herein to compute RR intensity enhancements would need to be replaced by a more general formalism based on derivatives of the polarizability tensor. 36 This might also be helpful for resolving experimental ambiguities regarding signals arising from lower-order nonlinear processes, which complicate the analysis of FSRS spectra. 9 These are interesting avenues for future work.…”

Section: Discussionmentioning

confidence: 99%

“…These simulations were performed using TD-DFT at the CAM-B3LYP/6-31G* level, for which the S 1 → S 2 transition energy is only slightly lower than the SOS-CIS(D) estimate (Table ) but where affordable analytic gradients are available in order to propagate trajectories on excited-state potential surfaces. Resonance Raman (RR) intensities, corresponding to the S 1 → S 2 electronic transition except where otherwise indicated, were computed at 10 fs intervals along the S 1 trajectory, according to the formula , which comes from the excited-state gradient (short-time) approximation, equivalent to the independent-mode displaced harmonic oscillator (IMDHO) model. − In eq , ω k is the frequency of the k th normal mode in the initial (S 1 ) state and Δ k is the dimensionless displacement of the k th normal mode between the initial and final states. The quantity ω L in eq is the laser frequency, which would be necessary to compute absolute RR intensities but which cancels in the excited-state formalism that is described in more detail below.…”

Section: Computational Detailsmentioning

confidence: 99%

See 2 more Smart Citations

Ab InitioApproach to Femtosecond Stimulated Raman Spectroscopy: Investigating Vibrational Modes Probed in Excited-State Relaxation of Quaterthiophenes

Dasgupta

Herbert

2020

J. Phys. Chem. A

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Femtosecond stimulated Raman spectroscopy (FSRS) is an ultrafast pump−probe technique designed to elucidate excited-state molecular dynamics by means of vibrational spectroscopy. We present a first-principles protocol for the simulation of FSRS that integrates ab initio molecular dynamics with computational resonance Raman spectroscopy. Theoretical calculations can monitor the time-dependent evolution of specific vibrational modes and thus provide insight into the nature of the motion responsible for the experimental FSRS signal, and we apply this technique to study quaterthiophene derivatives. The S 1 state of two different quaterthiophene derivatives relaxes via inphase and out-of-phase stretching modes whose frequencies are coupled to the dihedral backbone angle, such that the spectral evolution reflects the excited-state relaxation toward a planar conformation. The simulated spectra aid in confirming the experimental assignment of the vibrational modes that are probed in the existing FSRS experiments on quaterthiophenes.

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BODIPY‐Perylene Charge Transfer Compounds; Sensitizers for Triplet‐Triplet Annihilation Up‐conversion

Arellano-Reyes

Prabhakaran

Sia

et al. 2023

Chemistry A European J

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BODIPY heterochromophores, asymmetrically substituted with perylene and/or iodine at the 2 and 6 positions were prepared and investigated as sensitizers for triplet‐triplet annihilation up conversion (TTA‐UC). Single‐crystal X‐ray crystallographic analyses show that the torsion angle between BODIPY and perylene units lie between 73.54 and 74.51, though they are not orthogonal. Both compounds show intense, charge transfer absorption and emission profiles, confirmed by resonance Raman spectroscopy and consistent with DFT calculations. The emission quantum yield was solvent dependent but the emission profile remained characteristic of CT transition across all solvents explored. Both BODIPY derivatives were found to be effective sensitizers of TTA‐UC with perylene annihilator in dioxane and DMSO. Intense anti‐Stokes emission was observed, and visible by eye from these solvents. Conversely, no TTA‐UC was observed from the other solvents explored, including from non‐polar solvents such as toluene and hexane that yielded brightest fluorescence from the BODIPY derivatives. In dioxane, the power density plots obtained were strongly consistent with TTA‐UC and the power density threshold, the Ith value (the photon flux at which 50 % of ΦTTAUC is achieved), for B2PI was observed to be 2.5x lower than of B2P under optimal conditions, an effect ascribed to the combined influence of spin‐orbit charge transfer intersystem crossing (SOCT‐ISC) and heavy metal on the triplet state formation for B2PI.

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Calculation of Vibrational Resonance R aman Spectra of Molecules Using Quantum Chemistry Methods

Cited by 9 publications

References 162 publications

Ring Vibrations to Sense Anionic Ibuprofen in Aqueous Solution as Revealed by Resonance Raman

Ring Vibrations to Sense Anionic Ibuprofen in Aqueous Solution as Revealed by Resonance Raman

Ab InitioApproach to Femtosecond Stimulated Raman Spectroscopy: Investigating Vibrational Modes Probed in Excited-State Relaxation of Quaterthiophenes

BODIPY‐Perylene Charge Transfer Compounds; Sensitizers for Triplet‐Triplet Annihilation Up‐conversion

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