Reference interaction site model self-consistent field study for solvation effect on carbonyl compounds in aqueous solution

Abstract

In the previous study, Chem. Phys. Lett. 214, 391 (1993), we developed a new computational procedure for the solvation effect on the electronic structure of solute based upon the reference interaction site model (RISM) integral equation and the Hartree–Fock equation. The method enables us to calculate the solvent distribution and solute electronic wave functions simultaneously, which is free from such empirical parametrizations as appeared in the usual models based on the dielectric continuum picture. In the present article, we have applied the method to several carbonyl compounds in aqueous solution. The SPC model was used to describe the liquid water. The vertical n→π*, π→π*, and σ→π* transitions of formaldehyde are examined by the RISM-self-consistent field formalism coupled with the restricted Hartree–Fock approximation, and then the free energy calculation was performed for the excited state in order to estimate the contributions for the optical fluorescence spectra. The intramolecular energy turned out to give significant contribution to the bathochromic shift of fluorescence relative to the absorption in the liquid phase. Furthermore the importance of the structural effect of the functional group was discussed by the calculations of three more carbonyl compounds, acetaldehyde, acetone, and acrolein.

Hybrid Monte Carlo simulations of vertical electronic transitions in acetone in aqueous solution

“…1 [19,[34][35][36][37][38][39][40][41][42][43][44][45]. The shifts of the previous studies are in the range 0.14 to 0.38 eV; see Table 7 of Aidas et.al.…”

Conical intersections in solution: Formulation, algorithm, and implementation with combined quantum mechanics/molecular mechanics method

“…82,83 Kato et al, by using the linear response theory and Gaussian fluctuation model, developed a conical intersection optimization procedure of potential of mean force surfaces in solution, which employs the reference interaction site model with the complete active space selfconsistent field method. [84][85][86][87][88] Recently, Mori et al extended this method to use the multi-state complete active space second order perturbation theory. 87 Furthermore, Aguilar et al used the averaged solvent electrostatic potential from molecular dynamics simulations of solvents, as a perturbation potential embedded into Hamiltonian of solute, to optimize conical intersections in solution.…”

“…[89][90][91] Conical intersections of free energy surfaces, i.e., potential of mean force surfaces, are useful for understanding photophysical and photochemical processes in condensed phase. [82][83][84][85][86] First, it is usually expensive, even impossible, to search each local QM conical intersection structure related to each MM configuration. The MM subsystem mainly acts as a perturbation on the QM subsystem; thus, the structure and the energetics of the QM conical intersection change subtly as a result of a small position displacement of the MM subsystem.…”

A subsystem density-functional theory approach for the quantum chemical treatment of proteins

“…The gas-to-aqueous solution shift in electronic n → * absorption energy has previously been theoretically considered by using different electronic structure methods in combination with a variety of solvent models including a supermolecular approach, [54][55][56] the continuum solvation conductorlike screening model ͑COSMO͒, 57 reference interaction site model self-consistent field ͑RISM-SCF͒, 58 MD or Monte Carlo ͑MC͒ simulations followed by the QM/MM calculations 56,59,60 and QM/MM in combination with the polarizable continuum model ͑PCM͒. 61 In addition, the solvent effects on the → * absorption were studied in Refs.…”