原子与分子团簇
First principles calculations based on hybrid density functional theory have been used to study the electronic and geometric properties of armchair silicon and germanium nanotubes ranging from A (3, 3) through A (9, 9). The approach used is…
Absolute Ar XK (3 keV) and Xe XL (4 keV) photon yields are measured as a function of laser peak intensity, for large (104 - 105 atoms) argon and xenon clusters submitted to intense laser pulses. A clear threshold behavior is observed. The…
We investigate the heating of the quasi-free electrons in large rare gas clusters (N exceeding 10^5 atoms) by short laser pulses at moderate intensities (I~10^{15} Wcm^{-2}). We identify elastic large-angle backscattering of electrons at…
We analyze the dynamics of up to $10^5$ electrons resulting from illuminating a Xenon cluster with 9093 atoms with intense laser pulses of different length and peak intensity. Interesting details of electron motion are identified which can…
A crystalline form of LiBC is known which has been predicted to be superconducting, with a Tc comparable to that of MgB_2. In both compounds, superconductivity is enhanced by the presence of two electronic bands, one of which is close to a…
The two published lithium peroxide structures, both ascribed to the hexagonal P -6 space group, were subjected to reinterpretation and another more symmetric structure, now belonging to the P 63/m m c space group, was found. Detailed…
We report electronic and magnetic structure of arsenic-doped manganese clusters from density-functional theory using generalized gradient approximation for the exchange-correlation energy. We find that arsenic stabilizes manganese clusters,…
Low-energy structures are found on the potential energy surfaces of the neutral, cationic, and anionic gold clusters Au_{5 \leq n \leq 8}^Z (Z = 0, \pm) and on the neutral potential energy surface of Au_9. These structures provide insights…
A long-standing problem with the solution of the Schr\"odinger equation has been its inability to account for the electron-positron annihilation in positron hydrogen scattering above the positronium formation threshold. This letter shows…
The independent atom and electron model [1] is introduced in a quantum context and associated approximations tentatively estimated. Confrontation of the model to measured ionization and excitation cross sections of small ionic carbon…
Density--functional simulations have been performed on Na$_{55}$, Na$_{92}$ and Na$_{142}$ clusters in order to understand the experimentally observed melting properties [M. Schmidt \textit{et al.}, Nature (London) \textbf{393}, 238…
In this paper we employ the hydrodynamic formulation of time-dependent density functional theory to obtain the van der Waal coefficients $C_{6}$ and $C_{8}$ of alkali-metal clusters of various sizes including very large clusters. Such…
We present our recent results on the scattering length of ^4He-^4He_2 collisions. These investigations are based on the hard-core version of the Faddeev differential equations. As compared to our previous calculations of the same quantity,…
The theoretical formalism of the local density approximation (LDA) to density functional theory (DFT) has been used to study the electronic and geometric structures of SimCn (1<=m, n<=4;n<=m) clusters. An all electron 6-311++G** basis set…
In this work we have performed for the first time a systematic analysis of the dissociation and fission pathways of neutral, singly and doubly charged alanine dipeptide ions with the aim to identify the fission mechanism and the most…
We have investigated the potential energy surface for neutral and charged alanine and glycine chains consisting of up to 6 amino acids. For these molecules we have calculated potential energy surfaces as a function of the Ramachandran…
Static charge in and on the surface of pyroelectric crystals of LiNbO3 and LiTaO3 in a dilute gas has been shown to ionize gas molecules via electron tunneling. The released electrons and positive ions are focused and accelerated according…
Neutral silicon clusters Si_n (up to n = 7) and their cations Si_n+ (up to n = 10) have been produced by femtosecond laser ablation of bulk silicon in vacuum and investigated using time-of-flight mass spectrometry. Two populations of the…
The interaction of short laser pulses with small rare gas clusters is investigated by using a microscopic, semi-classical model with an explicit treatment of the inner-atomic dynamics. Field and collisional ionisation as well as…
An electron diffraction technique is used to study the structure of clusters formed in an isentropically expanding supersonic argon jet. The formation of the hcp phase with increasing cluster size is reliably detected for the first time.…