The absorption and fluorescence spectra of 4-(3-methoxybenzylidene)-2-methyl-oxazalone interpreted by Franck–Condon simulation in various pH solvent environments

Abstract

<p>The absorption and fluorescence spectra have been investigated and assigned by Franck–Condon (FC) simulations at quantum TDDFT level for 4-(3-methoxybenzylidene)-2-methyl-oxazalone (m-MeOBDI) dissolved in neutral, acidic, and basic solvent environments. Four...</p>

Unveiling the atomic‐electronegativity‐dependent ESIPT behavior for 4′‐dimethylamino‐flavonol chemosensor

“…In order to quantitatively provide the reaction processes and barriers in excited states, the behaviors of ESIPT reaction are studied by constructing potential energy curves (PECs). As is well known, the PECs can bring difficulties to normal chemical reactions in excited states along with a function of one or more geometric changes [58][59][60][61][62][63][64][65]. Via restrictive optimization method to construct the PECs for 4DF-O, 4DF-S, and 4DF-Se, we could obtain the PECs along with keeping elongating O 1 -H 2 bond distance from 0.90 to 2.15 Å in step of 0.05 Å that includes all the photoinduced tautomers (seen in Figure S1, ESI).…”

How to Predict Excited State Geometry by Using Empirical Parameters Obtained from Franck‐Condon Analysis of Optical Spectrum

“…[62][63][64][65][66] Nevertheless, the small vibronic intensity mismatch with the experiment (Figure 4) at high energies (above 37,500 cm À 1 ) is believed to be due to the inadequate theoretical description of Franck-Condon approximation of optical spectra. In some studies, the formula used for s abs w ð Þ has w dependence; [12,17,33,67] therefore, a better fit might be possible with those approaches for the high energy part of the absorption spectrum. Nonetheless, other methods and theories are both time consuming and tedious and they do not allow the use of simple spectral fit process to simulate the experimental spectrum which can then be used to extract the information about the excited states.…”

Correlating Stokes Shift with Huang‐Rhys Parameter for Diatomic Molecules: Effects of Finite Temperature, Anharmonicity and Breakdown of Franck‐Condon Approximation

“…[1][2][3][4][5][6][7][8] In computational chemistry, where ab initio and density functional calculations are routinely carried out to compute the molecular structure and energetics, the displaced harmonic oscillator model proves to be very helpful. [9][10][11] However, the harmonic approximation is valid only near the bottom of the potential surface; as the energy increases, the potential surfaces become distorted, the energy gap also becomes large between two electronic states, and the anharmonic effects become significant. The general method to treat the anharmonicity is to take a perturbative measure to the harmonic framework and to find an approximate solution.…”

“…For example, theoretical treatment of steady‐state optical spectra is mainly performed by calculating the Franck‐Condon (FC) overlap integrals between the vibrational wavefunctions belonging to two electronic states under the displaced harmonic normal mode basis [1–8] . In computational chemistry, where ab initio and density functional calculations are routinely carried out to compute the molecular structure and energetics, the displaced harmonic oscillator model proves to be very helpful [9–11] . However, the harmonic approximation is valid only near the bottom of the potential surface; as the energy increases, the potential surfaces become distorted, the energy gap also becomes large between two electronic states, and the anharmonic effects become significant.…”