Atomic and Molecular Clusters
Low-temperature (below 60K) phase changes of free clusters containing 50, 137, and 229 methane molecules have been observed in isoenergetic Molecular Dynamics computations. Bulk solid methane exhibits structural phase transformation at 20.4…
A new approach is introduced for calculating the spectral shifts of the most bathochromic pi -> pi* transition of an aromatic chromophore in apolar environments. As an example, perylene in solid and liquid n-alkane matrices was chosen, and…
Positively charged zinc oxide clusters ZnnOm (up to n = 16, m <= n) of various stoichiometry were synthesized in the gas phase by excimer ArF laser ablation of a ZnO target and investigated using time-of-flight mass spectrometry. Depending…
Rich populations of clusters have been observed after femtosecond laser ablation of bulk silicon in vacuum. Size and velocity distributions of the clusters as well as their charge states have been analyzed by reflectron time-of-flight mass…
We predict the strong enhancement in the photoabsorption of small Mg clusters in the region of 4-5 eV due to the resonant excitation of the plasmon oscillations of cluster electrons. The photoabsorption spectra for neutral Mg clusters…
The motion of electrons and ions in medium-sized rare gas clusters (1000 atoms) exposed to intense laser pulses is studied microscopically by means of classical molecular dynamics using a hierarchical tree code. Pulse parameters for optimum…
Some low-energy three-body muon- and electron-transfer processes are considered within the Faddeev-Hahn formulation using two-, six-, and ten-state close-coupling approximation. We test our approach in bound-state problems for systems…
Properties of low-energy (infra-red) quadrupole modes (LEQM) of multipolarity $+AFw-lambda+AFw-mu =$20, 21 and 22 in deformed sodium clusters are studied within the Kohn-Sham LDA RPA approach. Possible manifestations of LEQM in stimulated…
The surface plasmon in simple metal clusters is red-shifted from the Mie frequency, the energy shift being significantly larger than the usual spill-out correction. Here we develop a variational approach to the RPA collective excitations.…
Entangled states of two coupled polar molecules controlled by laser pulses are studied theoretically. Schmidt decomposition is used to measure the degree of entanglement. By varying the pulse shape of the applied laser, transition from…
We apply a hard-core version of the Faddeev differential equations to the ^3He^4He_2 three-atomic system. Employing the TTY interatomic potential by Tang, Toennies and Yiu we calculate the binding energy of the ^3He^4He_2 trimer and the…
We apply a hard-core version of the Faddeev differential equations to the ^3He^4He_2 three-atomic system. Using these equations we calculate the binding energy of the ^3He^4He_2 trimer with the LM2M2 potential by Aziz and Slaman and more…
In this work, we have investigated the interaction of a high-power Ar$^+$ laser beam, in a continuous multi-line regime, with Ag$^+$-doped glass samples. The samples were subjected to the irradiation after the ion-exchange step. As a result…
We present a genetic algorithm developed (GA) to optimize molecular AF_6 cluster configurations with respect to their energy. The method is based on the Darvin's evolutionary theory: structures with lowest energies survive in a system of…
We present a new theoretical framework for modelling the cluster growing process. Starting from the initial tetrahedral cluster configuration, adding new atoms to the system and absorbing its energy at each step, we find cluster growing…
It has previously been proven that finding the globally minimum energy configuration of an atomic cluster belongs in the class of NP-hard problems. However, this proof is limited only to homonuclear clusters. This paper presents a new proof…
Thermal stability properties and the melting-like transition of Na_n, n=13-147, clusters are studied through microcanonical molecular dynamics simulations. The metallic bonding in the sodium clusters is mimicked by a many-body Gupta…
An analytical expression of a Floquet operator, which describes the evolution of a wave packet in combined atomic and an intense laser field,is obtained approximately in the stabilization regime. Both the classical and quantum versions of…
The failure stresses and strains of nanotubes given by theoretical or numerical predictions are much higher than observed in experiments. We show that defects can explain part of this discrepancy: for an n-atom defect with 2<=n<=8, the…
Ga-rich GaAs (001) surfaces are successfully observed during high-temperature annealing by scanning tunneling microscopy (STM). With a substrate temperature of 550 C, reflection high-energy diffraction patterns and reflectance anisotropy…