The stereodynamics of the Ar þ NO ( j1⁄4 0) rotational inelastic excitation has been investigated at 66 meV by means of quasiclassical trajectories on a recent ab initio potential energy surface. A marked correlation between the preferred sense of rotation of NO and the scattering plane is obtained for the highest rotational levels accessible, which are excited in strong repulsive collisions. T...

A new method is proposed for locating saddle points on potential energy surfaces. The method involves walking on the ridge separating reactants’ and products’ valleys toward its minimum, which is a saddle point in coordinate space. Of particular advantage for ab inirio calculations, the ridge method does not require evaluation of second derivatives of the potential energy. Another important fea...

We study the effect of a spatially varying potential energy surface on the self-organization of nanoscale patterns during epitaxial growth. The computational approach is based on the level set method. Our results have an implication for guided self-assembly of nano patterns, which is a promising new technique for many technological applications. Both kinetic as well as thermodynamic effects can...

The cumulative reaction probability (CRP) (the Boltzmann average of which is the thermal rate constant) has been calculated for the reaction H,+OH++HzO+H in its full (six) dimensionality for total angular momentum J=O. The calculation, which should be the (numerically) exact result for the assumed potential energy surface, was carried out by a direct procedure that avoids having to solve the co...

In this chapter the physical aspects of the global optimization of the geometry of atomic clusters are elucidated. In particular, I examine the structural principles that determine the nature of the lowest-energy structure, the physical reasons why some clusters are especially difficult to optimize and how the basin-hopping transformation of the potential energy surface enables these difficult ...

The photodynamics of bacteriorhodopsin were studied by transient absorption and gain measurements after excitation with femtosecond pulses at 620 nm. With probing pulses at longer wavelengths (A> 770 nm) the previously reported formation of the J intermediate (with a time constant of 500f 100 fs) was confirmed. With probing pulses around 700 nm, a faster process with a relaxation time of 200 rt...

The infrared photodissociation spectrum of the degenerate asymmetric CH stretch (n3) vibration of the CH3 –He ionic complex has been recorded. The rotational structure and vibrational frequency of the observed transition are consistent with a p-bonded C3v cluster geometry where the He ligand is attached to the 2pz orbital of the central C atom of CH3 1 . The intermolecular bond in the ground vi...

Potential energy surfaces of N,N-hydrogen migration of pyrazole and 5-methyl pyrazole for the ground and triplet states were calculated by the ab initio molecular orbital methods. All potential energy surfaces for the N.N-hydrogen shift have high energy barriers. The occurrence of the structural change indispensable to the switching function is doubtful for pyrazole and 5-methyl pyrazole. The s...

Jeffrey T. Scruggs Lamine Mili The Bradley Department of Electrical and Computer Engineering Virginia Polytechnic Institute and State University Blacksburg, VA 24061-0111 Abstract – In methods for assessing the critical clearing time based on the transient energy function, the dominant procedures in use for detecting the exit point across the Potential Energy Boundary Surface (PEBS) are the ray...

We present an overview of the recent studies on the properties of the potential energy surface for a simple model of water. We emphasize the relations between PES properties and dynamics in supercooled states for the model and discuss possible future application of the PES studies. PACS. 61.43.Fs Glasses – 64.70.Pf Glass transitions – 66.10.Cb Diffusion and thermal diffusion