In the present work, we have computed the energy and hardness profiles for a series of inter and intramolecular conformational changes at several levels of calculation. All processes studied have in common the fact that the choice of a weak methodology or a poor basis set results in the presence of spurious stationary points in the energy profile. At variance with the energy profiles, the hardn...

We investigate the collective properties of particles in a 2D experimental system which consists of a bi-disperse mixture of colloidal particles confined at an air/water interface. We find a direct correlation between structure and dynamical heterogeneities in this system: particles belonging to locally ordered structures have lower potential energy and are slower than other particles. In a mor...

The functions of biological macromolecules are inherently linked to their complex conformational behaviour. As a consequence of this complexity, the corresponding potential energy landscapes encompass multiple minima. Some of the intermediate structures between initial and final states can be characterized by experimental techniques. Computer simulations can explore the dynamics of individual s...

Dissociation under ultrashort intense laser fields differs from the process occurring in the presence of a weak field by two main characteristics. In the strong field regime, the force exerted by the laser on the molecule is comparable to the intermolecular forces. In addition, this force is varying on a time scale comparable to that of the molecular vibration. The combination of these two effe...

The real time photodissociation dynamics of CH(3)I from the A band has been studied experimentally and theoretically. Femtosecond pump-probe experiments in combination with velocity map imaging have been carried out to measure the reaction times (clocking) of the different (nonadiabatic) channels of this photodissociation reaction yielding ground and spin-orbit excited states of the I fragment ...

Tight-binding molecular dynamics simulations of the adsorption of O2/Pt(111) have been performed based on an ab initio potential energy surface. We demonstrate that, contrary to common belief, in this system the whole adsorption probability as a function of the kinetic energy can be understood in terms of trapping into chemisorbed molecular precursor states. This provides a novel unified pictur...

A space warping method, facilitating the modeling of large-scale conformational changes in mesoscopic systems, is presented. The method uses a set of "global (or collective) coordinates" that capture overall behavior, in conjunction with the set of atomic coordinates. Application of the space warping method to energy minimization is discussed. Several simulations where the method is used to det...

High-resolution spectroscopy measures the transitions between energy levels with high accuracy; typically, uncertainties are in the region of 1 part in 108. Although it is possible, under favorable circumstances, to obtain this sort of accuracy by fitting effective Hamiltonians to observed spectra (see Bauder 2011: Fundamentals of Rotational Spectroscopy, this handbook), such ultrahigh accuracy...