Isotopic effects in the S1 exited state of anthranilic acid deuterated in various positions in substituent groups. Supersonic-jet LIF spectroscopy and CC2 ab initio study

Kolek, Przemysław; Andrzejak, Marcin; Najbar, Jan; Ostrowska-Kopeć, Małgorzata; Piotrowska, Izabela

doi:10.1016/j.chemphys.2015.02.005

Cited by 4 publications

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“…Calculated versus Experimental41 Relative Shifts [in cm−1 ] of the 0−0 Bands for Different Isotopomers of AA a Δ stands for the errors between the calculated and the experimental values.…”

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confidence: 99%

Theoretical Modeling of Deuteration-Induced Shifts of the 0–0 Bands in Absorption Spectra of Selected Aromatic Amines: The Role of the Double-Well Potential

Andrzejak

Kolek

2013

J. Phys. Chem. A

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The harmonic approximation fails for inversion of the NH2 group in the ground state of aromatic amines as this vibration is characterized by a symmetric double-well potential with relatively small energy barrier. In such cases, the standard harmonic vibrational analysis is inapplicable: the inversion frequency calculated for the bottom of the potential well is strongly overestimated, while it attains imaginary values for the planar conformation of the molecule. The model calculations are discussed taking explicitly into account the presence of the double-well potential. The study is initially focused on reproduction of the deuteration-induced shifts of the 0-0 absorption band for anthranilic acid. The (incorrect) harmonic frequency of the NH2 inversion is replaced by a better one, obtained from numerical calculations employing a simple, quartic-quadratic model for the double-well potential, which is parametrized using just the harmonic frequency of the inversion and the height of the energy barrier. This operation brings theoretical results to qualitative agreement with experiment. A still better match is achieved with a modified version of the model that accounts for mixing of the NH2 inversion mode with other normal modes while retaining the initial simplicity of one-dimensional approach. The corrected results show surprisingly good accuracy, with deviations of the calculated shifts from the experimental values reduced to less than 5 cm(-1). In order to test the performance of the model for systems with higher energy barrier for the NH2 inversion, we have measured the LIF excitation spectra of three different amminobenzonitriles. Partial assignment of the 0-0 bands has been achieved based on their relative intensities for samples with different isotopic exchange ratios. Calculated shifts are in excellent agreement with experimental values for the identified bands. Theoretical predictions are used to complete the assignment of the 0-0 bands in the spectra of the studied amminobenzonitriles.

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Theoretical Modeling of Deuteration-Induced Shifts of the 0–0 Bands in Absorption Spectra of Selected Aromatic Amines: The Role of the Double-Well Potential

Andrzejak

Kolek

2013

J. Phys. Chem. A

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“…LIF excitation spectra of AA of improved resolution, better S/N ratio and minimized saturation effects − provided extensive experimental data for the Franck–Condon analysis of the S 0 → S 1 transition based on the TD-DFT and CIS (single CI) calculations . The FC analysis and the studies of other aniline derivatives showed that the band intensities computed using the CIS method, and hence the geometry changes, are drastically underestimated, especially ortho -substituted molecules.…”

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Quantitatively Adequate Calculations of the H-Chelate Ring Distortion upon the S₀ → S₁(ππ*) Excitation in Internally H-Bonded o-Anthranilic Acid: CC2 Coupled-Cluster versus TDDFT

et al. 2018

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The S → S(π → π*) excitation in o-aminobenzoic acid causes strengthening of the N-H···O intramolecular hydrogen bond. The interplay of the hydrogen bond shortening, the hydrogen atom dislocation along the hydrogen bond, and the skeletal relaxation is investigated. These effects often cause the appearance of dual fluorescence from the π-conjugated internally H-bonded molecules, which is traditionally interpreted as the evidence of the excited-state intramolecular proton transfer process: ESPIT. Hence, their quantitative modeling is an important but demanding task for computational photochemistry. Extensive calculations using CC2 method (the perturbative approximation to CCSD coupled-cluster) and TDDFT(B3LYP) were performed with the series of (aug)-cc-pVXZ(X = D,T,Q) basis sets. CC2 predicts remarkable shortening of the O···H distance by 0.273 Å accompanied by the skeleton relaxation that involves considerable distortions of valence angles of the amino group (up to 7.3°) and within the benzene ring (up to 5°). Additionally, moderate changes (<0.046 Å) of the bond alternation in the π-electronic system and the hydrogen atom dislocation along the hydrogen bond (0.043 Å) are predicted. The CC2 method yields 90% of the magnitude of the experimentally based geometry changes, estimated in the earlier studies via Franck-Condon fit to the LIF spectra, while the TDDFT results approach only 65% of the experimental values.

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Consistent Franck–Condon modeling of geometry changes for the S0→S1(ππ*) excitation in anthranilic acid: LIF spectroscopy aided by CC2 or TDDFT vibrations

Kolek

Andrzejak

Uchacz

et al. 2020

Journal of Quantitative Spectroscopy and Radiative Transfer

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Isotopic effects in the S1 exited state of anthranilic acid deuterated in various positions in substituent groups. Supersonic-jet LIF spectroscopy and CC2 ab initio study

Cited by 4 publications

References 29 publications

Theoretical Modeling of Deuteration-Induced Shifts of the 0–0 Bands in Absorption Spectra of Selected Aromatic Amines: The Role of the Double-Well Potential

Theoretical Modeling of Deuteration-Induced Shifts of the 0–0 Bands in Absorption Spectra of Selected Aromatic Amines: The Role of the Double-Well Potential

Quantitatively Adequate Calculations of the H-Chelate Ring Distortion upon the S₀ → S₁(ππ*) Excitation in Internally H-Bonded o-Anthranilic Acid: CC2 Coupled-Cluster versus TDDFT

Consistent Franck–Condon modeling of geometry changes for the S0→S1(ππ*) excitation in anthranilic acid: LIF spectroscopy aided by CC2 or TDDFT vibrations

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Isotopic effects in the S1 exited state of anthranilic acid deuterated in various positions in substituent groups. Supersonic-jet LIF spectroscopy and CC2 ab initio study

Cited by 4 publications

References 29 publications

Theoretical Modeling of Deuteration-Induced Shifts of the 0–0 Bands in Absorption Spectra of Selected Aromatic Amines: The Role of the Double-Well Potential

Theoretical Modeling of Deuteration-Induced Shifts of the 0–0 Bands in Absorption Spectra of Selected Aromatic Amines: The Role of the Double-Well Potential

Quantitatively Adequate Calculations of the H-Chelate Ring Distortion upon the S0 → S1(ππ*) Excitation in Internally H-Bonded o-Anthranilic Acid: CC2 Coupled-Cluster versus TDDFT

Consistent Franck–Condon modeling of geometry changes for the S0→S1(ππ*) excitation in anthranilic acid: LIF spectroscopy aided by CC2 or TDDFT vibrations

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Quantitatively Adequate Calculations of the H-Chelate Ring Distortion upon the S₀ → S₁(ππ*) Excitation in Internally H-Bonded o-Anthranilic Acid: CC2 Coupled-Cluster versus TDDFT