Charge States of Bare Silicon Clusters up to Si8 by Non-Conventional Tight-Binding Method

A recently developed non-conventional tight-binding method was applied in combination with molecular dynamics to compute the geometric structures and cohesion energies of small stable pure Si clusters containing from 3 to 8 atoms, in neutral, positive and negative charge states. The influence of the charge state on the cluster configuration and cohesion energy is considered. The Anderson U(-) effect is observed in Si3-Si5 clusters. Doubly positively charged states are found to be the most energetically stable form for all clusters considered. The results computed with this semi-empirical approach are compared to predictions from state-of-the-art ab initio methods

Charge States of Bare Silicon Clusters up to Si8 by Non-Conventional Tight-Binding Method

A recently developed non-conventional tight-binding method was applied in combination with molecular dynamics to compute the geometric structures and cohesion energies of small stable pure Si clusters containing from 3 to 8 atoms, in neutral, positive and negative charge states. The influence of the charge state on the cluster configuration and cohesion energy is considered. The Anderson U(-) effect is observed in Si3-Si5 clusters. Doubly positively charged states are found to be the most energetically stable form for all clusters considered. The results computed with this semi-empirical approach are compared to predictions from state-of-the-art ab initio methods

Structure and Charge States of the Selected Hydrogenated Silicon Clusters Si2-Si8 by Non-Conventional Tight-Binding Method

Structures of SinHm clusters in neutral, positive and double positive charge states have been calculated by nonconventional tight-binding method and molecular dynamics. An influence of the charge state and the termination by hydrogen of dangling bonds on cluster structures those are obtained as a result of chemical vapor precipitation in silane, is considered for the first time. Fully hydrogenated clusters have tetrahedral branched structures. Other isomers have forms of closed circles

Ionosphere Monitoring

Global navigation satellite system (GSSS)-based monitoring of the ionosphere is important in a twofold manner. Firstly, GNSS measurements provide valuable ionospheric information for correcting and mitigating ionospheric range errors or to warn users in particular in precise and safety of life (SoL) applications. Secondly, spatial and temporal resolution of ground- and space-based measurements is high enough to explore the dynamics of ionospheric processes such as the origin and propagation of ionospheric storms. It is discussed how ground- and space-based GNSS measurements are used to create globalmaps of total electron content (TEC) and to reconstruct the highly variable three-dimensional (3-D) electron density distribution on global scale under perturbed conditions. Thus, the monitoring results can be used for correcting ionospheric errors in single-frequency applications as well as for studying the driving forces of space weather-induced perturbation features at a broad range of temporal and spatial scales. Whereas large- and mediumscale perturbations affect accuracy and reliability of GNSS measurements, small-scale plasma irregularities and plasma bubbles have a direct impact on the continuity of GNSS availability by causing strong and rapid fluctuations of the signal strength, known as radio scintillations. It is discussed how better understanding of space weather-related phenomena may help to model and forecast ionospheric behavior even under perturbed conditions. Hence, ionospheric monitoring contributes to the successful mitigation of range errors or performance degradation associated with the ionospheric impact on a broad spectrum of GNSS applications