Recent high-resolution soft X–ray resonant inelastic X-ray scattering technique enables us to distinguish valence electronic structure of water molecules having different hydrogen-bond configurations in the liquid phase. Moreover, in the elastic region, well-separated multiple vibrational structures appear, which corresponds to the internal OH stretch vibration in the ground state. Both the val...

We have used a variational approach to calculate some thermodynamic properties of the quasi-one dimensional liquid 3He such as the energy, entropy, free energy, equation of state and heat capacity at finite temperature. We have employed the Lennard-Jones potential as the inter-atomic interaction. We have seen that the total energy increases by increasing both temperature and density....

     In this study, the effect of the secondary structure of the protein on the acid strength of three structures of random (R), alpha helix (α) and beta sheet (b) were investigated theoretically. These structures are related to the cationic amino acids of histidine and lysine in the polypeptide chain of eight-glycine residue. Computational methods at the HF, B3LYP, X3LYP and M05-2X levels in t...

We extend the McPherson model for Si-O bond-breakage energetics, which considers only a single SiO4 tetrahedron, in a way to capture the effect of the whole crystal. No ledge in the direction assumed in the McPherson model was revealed. Instead, potential profiles feature a saddle point in a different direction. The activation energy for bond-breakage is found to be rather high (~ 6 eV). This s...

We apply a combination of state-of-the-art experimental and quantum-chemical methods to elucidate the electronic and chemical energetics of hydrogen adduction to a model open-shell graphene fragment. The lowest-energy adduct, 1H-phenalene, is determined to have a bond dissociation energy of 258.1 kJ mol-1, while other isomers exhibit reduced or in some cases negative bond dissociation energies,...

We develop a resummed thermodynamic perturbation theory for bond cooperativity in associating fluids by extension of Wertheim's multi-density formalism. We specifically consider the case of an associating hard sphere with two association sites and both pairwise and triplet contributions to the energy, such that the first bond in an associated cluster receives an energy -ε((1)) and each subseque...

The effect of C–C–C bond bending on the photodissociation of cyclobutane to form two ethylene molecules was investigated by performing semiclassical electron-radiation-ion dynamics simulations and also by examining the potential energy surfaces of the electronic ground state and lowest excited states. These potential energy surfaces, calculated at the CASSCF/MRPT2 level with 6-31G* basis sets a...

The double bond photoisomerization of fulvene has been studied with quantum dynamics calculations using the multi-configuration time-dependent Hartree method. Fulvene is a test case to develop optical control strategies based on the knowledge of the excited state decay mechanism. The decay takes place on a time scale of several hundred femtoseconds, and the potential energy surface is centered ...

It is shown how previously reported bond energy equations (Van Hooydonk, 1973) can be re­ generated starting from the assumptions (i) that the valence-orbital energy of an element in a bond can be expressed as a function of its occupancy number (Iczkowski-Margrave, 1961) and (ii) that the potential around an atom in a bond vanishes as soon as its valence orbital is doubly occupied (Ferreira, 19...