Ivan Vladimirovich Rostov

Australian National University | ANU · National Computational Infrastructure ( NCI)/ ANU Supercomputer Facility (ANUSF)

The interactions of the metal ions Na(+), Mg(2+), Ca(2+) and Zn(2+) with cytosine have been investigated with inclusion of solvent effects. Computations have been performed at the density functional and Møller-Plesset levels of theory within the IEFPCM solvent model. It has been found that the inclusion of the solvent environment is essential for g...

Earlier results for the 11-cis to all-trans isomerisation of the retinal chromophore after photoexcitation, studied using time-dependent density functional theory with the hybrid CAM-B3LYP functional, are compared with new results using other long-range corrected DFT functionals. The TDDFT S 0 and S 1 minimum energy paths have been compared with th...

The isomerization of the 11-cis isomer (PSB11) of the retinal chromophore to its all-trans isomer (PSBT) is examined. Optimized structures on both the ground state and the excited state are calculated, and the dependence on torsional angles in the carbon chain is investigated. Time-dependent density functional theory is used to produce excitation e...

We present a two-dimensional grid method for the calculation of complete free-energy surfaces for enzyme reactions using a hybrid quantum mechanical/molecular mechanical (QM/MM) potential within the semiempirical (PM3) QM approximation. This implementation is novel in that parallel processing with multiple trajectories (replica-exchange molecular d...

Outersphere reorganization energies (lambda) for intramolecular electron and hole transfer are studied in anion- and cation-radical forms of complex organic substrates (p-phenylphenyl-spacer-naphthyl) in polar (water, 1,2-dichloroethane, tetrahydrofuran) and quadrupolar (supercritical CO2) solvents. Structure and charge distributions of solute mole...

The goal of this chapter is to outline the special challenges faced in using computational methods to define the reaction mechanisms of enzymes. Our approach is to set the problem in the context of the special chemical and structural features which differentiate enzymes from other types of catalysts, and the limitations of experiment in probing the...

Outersphere reorganization energies (λ) for intramolecular electron transfer (ET) and hole transfer are studied in anion- and cation-radical forms of complex organic substrates (biphenylyl-spacer-naphtyl) in polar solvents simulated by means of the nonpolarizable models of water and 1,2-dichloroethane. The earlier elaborated molecular/continuum app...

We present calculations for various properties of the ground and excited states of several arylamine-substituted acridinium ion systems that have been studied experimentally. Using ab initio and semiempirical quantum mechanical methods together with the generalized Mulliken-Hush (GMH) model, we examine the excitation energies, dipole moment shifts,...

The hybrid molecular–continuum model for polar solvation considered in this paper combines the dielectric continuum approximation for treating fast electronic (inertialess) polarization effects and a molecular dynamics (MD) simulation for the slow (inertial) polarization component, including orientational and translational solvent modes. The inerti...

This paper presents a theoretical formulation for electron transfer coupled to the motion of multiple protons. This theory is applied to proton-coupled electron transfer PCET through amidinium– carboxylate salt bridges, where the electron transfer reaction is coupled to the motion of two protons at the proton transfer interface. The rate for the do...

A method of calculation of a free-energy surface (FES) of the proton transfer (PT) reaction in a polar aprotic solvent is developed. This is based on the two-state (valence bond) VB description of the solute combined with recent continuum medium models. Its essential new feature is an explicit quantum-chemical treatment of VB wave functions, includ...

Some recent advances in dielectric continuum models for static and dynamic aspects of molecular solvation are discussed, and connections with molecular-level solvent models are noted. The traditional Born-Onsager-Kirkwood (BKO) model is compared to a more flexible model (the so-called frequency-resolved cavity model (FRCM)) which assigns distinct i...

The frequency-resolved cavity model (FRCM), a generalized continuum reaction field model, which allows for distinct effective solute cavities pertaining to optical (op) and inertial (in) solvent response, has been implemented and applied to the evaluation of solvent reorganization energy (Es) for a number of intramolecular electron transfer (ET) pr...

The Born–Oppenheimer (BO) formulation of polar solvation is developed and implemented at the semiemperical (PM3) configuration interaction (CI) level, yielding estimates of electron transfer (ET) coupling elements (V0) for intramolecular ET in several families of radical ion systems. In contrast to the traditional treatment based on a single solven...

A refined continuum medium model, denoted as the `frequency-resolved cavity model' (FRCM), for describing solvation effects of electrically charged solutes in polar solvents is considered. The principal distinction between the commonly accepted Born–Kirkwood–Onsager model and the FRCM treatment is that in the latter case the medium polarization fie...

Important energy quantities governing electron transfer (ET) kinetics in polar solutions (reorganization energy, Er, and net free energy change, ΔU) are evaluated on the basis of quantum-chemical self-consistent reaction-field (SCRF) models. Either self-consistent field (SCF) or configuration interaction (CI) wavefunctions are used for the solute,...

The semiempirical AM1 method is used to calculate the transition states of the reaction of chlorine addition to ethylene in the gas phase and in a polar medium. The reaction complex in the polar medium incorporates a water molecule presumably having a catalytic effect on the process. The participation of water does decrease the energy of the transi...

Semiempirical AM1, PM3, and MINDO/3 calculations are performed to obtain the transitions states of chlorination of ethylene and cis-2-butene in the gas phase and taking medium effects into consideration. Two types of transition states were found for chlorination of ethylene in the gas phase, a low-polarity state corresponding to the molecular addit...