We develop a continuous variable neighborhood search heuristic for minimizing the potential energy function of a molecule. Computing the global minimum of this function is very difficult because it has a large number of local minimizers which grows exponentially with molecule size. Experimental evidence shows that in the great majority of cases the global minimum potential energy of a given mol...

A global double many-body expansion potential energy surface is reported for the electronic ground state of H2S by fitting accurate ab initio energies calculated at the multireference configuration interaction level with the aug-cc-pVQZ basis set, after slightly correcting semiempirically the dynamical correlation by the double many-body expansion-scaled external correlation method. The functio...

A real pendulum with friction will oscillate for a while after a short push, but will eventually come to rest close to a location where is potential energy has a minimum. If the system is closed, i.e. without a source of energy, it will eventually stop moving at a location near a minimum of the potential, no matter what type of friction force acts on the pendulum. This ‘variation principle’ is ...

Undoubtedly, the DLVO theory has been and it is still very useful for explaining the stability of colloidal dispersions. This theory was independently developed by Derjaguin and Landau [1] and by Verwey and Overbeek [2] in the forties. According to this theory, the total interaction potential (VT) between two colloidal particles is the sum of the repulsive electrostatic interaction energy (VE) ...

The string method originally proposed for the computation of minimum energy paths (MEPs) is modified to find saddle points around a given minimum on a potential energy landscape using the location of this minimum as only input. In the modified method the string is evolved by gradient flow in path space, with one of its end points fixed at the minimum and the other end point (the climbing image)...

We present results of computer experiments that indicate that several RNAs for which the native state (minimum free energy secondary structure) is functionally important (type III hammerhead ribozymes, signal recognition particle RNAs, U2 small nucleolar spliceosomal RNAs, certain riboswitches, etc.) all have lower folding energy than random RNAs of the same length and dinucleotide frequency. A...

We study the potential energy landscape ~many-atom potential energy as a function of atomic positions! of solid hcp He in the vicinity of the 0 K crystal structure using an accurate pair potential. At the melting point, the potential energy of the helium lattice is far above the minimum hcp interatomic potential energy. We confirm previous conclusions ~based on less accurate potentials! that al...

The availability of collisional rate coefficients is a prerequisite for an accurate interpretation of astrophysical observations, since the observed media often harbour densities where molecules are populated under non-local thermodynamic equilibrium conditions. In the current study, we present calculations of rate coefficients suitable to describe the various spin isomers ofmultiply deuterated...

The high resolution absorption spectrum of monodeuterated water, HDO, has been recorded by Intracavity Laser Absorption Spectroscopy (ICLAS) in the 12145–13160 cm 1 region. The achieved sensitivity (noise equivalent absorption on the order of amin 10 9 cm ) allowed detecting transitions with line strengths as weak as 10 27 cm/molecule which is about 50 times lower than the weakest line intensit...