A quantum mechanics/molecular mechanics (QM/MM) implementation that uses the Gaussian electrostatic model (GEM) as the MM force field is presented. GEM relies on the reproduction of electronic density by using auxiliary basis sets to calculate each component of the intermolecular interaction. This hybrid method has been used, along with a conventional QM/MM (point charges) method, to determine ...

The performance of the Hartree-Fock method and the three density functionals B3LYP, PBE0, and CAM-B3LYP is compared to results based on the coupled cluster singles and doubles model in predictions of the solvatochromic effects on the vertical n-->pi* and pi-->pi* electronic excitation energies of acrolein. All electronic structure methods employed the same solvent model, which is based on the c...

As assemblies of graphene sheets, carbon nanotubes, and fullerenes become components of new nanotechnologies, it is important to be able to predict the structures and properties of these systems. A problem has been that the level of quantum mechanics practical for such systems (density functional theory at the PBE level) cannot describe the London dispersion forces responsible for interaction o...

Mechanics of the Adhesive Properties of Ivy Nanoparticles Report Title The research objective of this proposal is to study the fundamental mechanics and mechanical properties of the nanoparticles-based adhesive secretion produced by ivy rootlets for surface affixing and climbing. Both experimental and theoretical studies will be conducted. More generally, we aim to use insight from nature to el...

we present detailed theoretical studies of the h-bonded complexes formed from interaction between 5-fluorouracil and various six-membered cyclic nitrosamine compounds. in this study, an investigation on intermolecular interactions in x-nu (x = ch2, sih2,bh, alh, nh, ph, o and s) complexes is carried out using density functional theory. the calculations are conducted on b3lyp/6-311++‏‏g** level ...

The nature of molecular interactions is examined. Intermolecular forces are divided into long-range and short-range components; the former operate at distances where the effects of electron exchange are negligible and decrease as an inverse power of the separation. The long-range interactions may be subdividied into electrostatic, induction and dispersion contributions, where the electrostatic ...

Vibrational spectroscopy is one of the most important experimental techniques for characterization molecules and materials. Spectroscopic signatures retrieved in experiments are not always easy to explain terms structure dynamics studied samples. Computational studies a crucial tool helping understand predict results. Molecular simulations have emerged as an attractive method simulation vibrati...

In this paper, NMR and QTAIM analysis for three substituted of T2SA complex was investigated in the gas and four solvents at DFT level. Intermolecular O–H…N hydrogen bonds between 1,2,4,5-Tetrazine and Sulphurous acids enhance the stability of complex.1,2,4,5-Tetrazine is a highly reactive diene for [4+2] inverse-Diels–Alder cycloaddition processes and an excellent precursor to attain the pyrid...