Long-range non-covalent interactions play a key role in the chemistry of natural polyphenols. We have previously proposed a description of supramolecular polyphenol complexes by the B3P86 density functional coupled with some corrections for dispersion. We couple here the B3P86 functional with the D3 correction for dispersion, assessing systematically the accuracy of the new B3P86-D3 model using...

The simple carbon-carbon scission of ethane is investigated by performing quantum mechanical calculations. The approach described in this paper was developed to determine dissociation rate constants for both small and large organic molecules, such as n-alkanes or alkyl-benzenes, for reasonable ranges of computation time and accuracy. The methodology that we propose is based on generalized trans...

A direct ab initio dynamics study on the gas-phase reactions of atomic hydrogen with different fluoromethanes has been carried out. The thermal rate constants were calculated using canonical variational transition state (CVT) theory augmented by multidimensional semiclassical zero and small curvature tunneling approximations. The potential energy surfaces for the reactions were calculated using...

A 35-year-old Caucasian female G4P4 at week one post partum with no significant past medical history was referred to our clinic for evaluation and treatment of right thigh dermatitis. Reported history suggested a recurrent dermatitis in the same location of which she believed the papules had been larger during the previous flare. Physical exam confirmed the lesions were localized to the distal ...

In the title mol-ecule, C(11)H(11)ClN(2)O, the pyrido[1,2-a]pyrimidine ring system is planar (maximum deviation = 0.0148 Å) and the methyl C and carbonyl O atoms are nearly coplanar to it. The chloro-ethyl side chain is in a synclinal conformation, nearly orthogonal to the pyrimidine ring, with a dihedral angle between the chloro-ethyl side chain and the pyrimidine ring of 88.5 (1)°. Weak inter...

The Sakurai-Sugiura projection (SS) method was implemented and numerically assessed for diagonalization of the Hamiltonian in time-dependent density functional theory (TDDFT). Since the SS method can be used to specify the range in which the eigenvalues are computed, it may be an efficient tool for use with eigenvalues in a particular range. In this article, the SS method is applied to core exc...

Solid state IR and Raman as well as aqueous solution state Raman spectra are reported for the linear di-amino acid peptide L-aspartyl-L-glutamic acid (L-Asp-L-Glu); the solution state Raman spectrum has also been obtained for the N,O-deuterated derivative. SCF-DFT calculations at the B3-LYP/cc-pVDZ level established that the structure and vibrational spectra of L-Asp-L-Glu can be interpreted us...

Chlorophylls have been extensively investigated both experimentally and theoretically owing to the fact that they are essential for photosynthesis. In the reported study, two forms of chlorophyll, chlorophyll a and chlorophyll b, were investigated by means of the density functional theory. Optimization of the S0, S1 and T1 states was performed with the B3-LYP functional. The computed fluorescen...