Topological characteristics of multidimensional potential energy surfaces are explored and the full conformation space is mapped on the set of local minima. This map partitions conformation space into energy-dependent or temperature-dependent ‘‘attraction basins’’ and generates a ‘‘disconnectivity’’ graph that reflects the basin connectivity and characterizes the shape of the multidimensional s...

Classical trajectory calculations for the unimolecular dissociation of nonrotating H2O, DHO, and MuHO are reported for different distributions of energy among the three vibrational normal modes. The calculations employ a realistic energy-switching potential energy surface for the electronic ground state of the water molecule. It is found that the unimolecular decay rates vary with the vibration...

Thermally driven chemistry as well as materials’ functionality are determined by the potential energy surface of a systems electronic ground state. This makes the potential energy surface a central and powerful concept in physics, chemistry and materials science. However, direct experimental access to the potential energy surface locally around atomic centers and to its long-range structure are...

Using an ab initio approach involving a non-empirical pseudopotentials for Na and Rb atoms, the adiabatic potential energy curves of 26 electronic states of NaRb ionic molecule dissociating up to Na(4p) + Rb and Na + Rb(7s) have been investigated. Their molecular spectroscopic constants have been derived and compared with the available theoretical works. Furthermore, the transition dipole momen...

We review the young field of ab initio molecular dynamics applied to molecule-surface reactions. The techniques of ab initio molecular dynamics include methods that use an analytic potential energy function fit to ab initio data and those that are fully ab initio. In this review, we focus on the insights provided by ab initio-based molecular dynamics that are currently unavailable from experime...

Thermal rate constants are calculated for the H + CH(4) --> CH(3) + H(2) reaction employing the potential energy surface of Espinosa-Garcia (Espinosa-Garcia, J. J. Chem. Phys. 2002, 116, 10664). Two theoretical approaches are used. First, we employ the multiconfigurational time-dependent Hartree method combined with flux correlation functions. In this way rate constants in the range 225-400 K a...

The Diels–Alder reaction is a powerful tool in organic synthesis and in the chemical industry. Recently an increased attention has been focused on the development of green methods for the purpose of improving rate and selectivity of this reaction. In recent years, ionic liquids (ILs) have gained a lot of attention as green solvents in organic synthesis and other chemical processes. This is main...

A satisfactory account of the van der Waals (London dispersion) forces is, in general, not possible by the Kohn-Sham method using standard local, semi-local GGA or meta-GGA density functionals. The recently proposed range-separated hybrid (RSH) approach, supplemented by second order perturbational corrections (MP2) to include long range dynamic correlation effects offers a physically consistent...

The conformational preferences of benznidazole were examined through the application of DFT, PCM and QTAIM calculations, whose results were compared with crystallography data. The geometries were fully optimized with minimum potential energy surface by means of the Relaxed Potential Energy Surface Scan (RPESS) at AM1, followed by the B3LYP/6-311++G(d,p) theoretical level. As a result, the s-cis...

The results of a 5D ab initio quantum dynamical study of the vinylidene acetylene isomerization reaction are presented. The study is based on a new ab initio potential energy surface for the planar system, obtained with the CCSD(T) method and the cc-pVTZ basis set. The dynamics is studied with grid methods, using 4-atom Jacobi-like coordinates and wave packet propagation techniques. The results...