|Ultima descărcare din IBN:|
| SM ISO690:2012|
KANAROVSKY, Evghenii; YALTYCHENKO, Olga; GORINCHOY, Natalia. Simulation of electron localization dynamics in coated metal nanoclusters in external electric field with allowance for polarization. In: Achievements and perspectives of modern chemistry. 9-11 octombrie 2019, Chişinău. Chisinau, Republic of Moldova: Tipografia Academiei de Ştiinţe a Moldovei, 2019, p. 118. ISBN 978-9975-62-428-2.
|Achievements and perspectives of modern chemistry 2019|
Conferința "International Conference "Achievements and perspectives of modern chemistry"" |
Chişinău, Moldova, 9-11 octombrie 2019
The elaboration of models for describing of the various processes occurring in the nanostructured composite materials (NSCM) containing the nanocluster inclusions is very important both from the theoretical point of view and for the practical applications. The model presented in this paper describes the electron localization-delocalization process in the coated metal nanocluster (NC) in the low-frequency external electric field (EEF), using as an example the tetramer NC in its different conformations (linear and planar-square). So that, in addition to the tunneling of a common electron between the NC centers, the polarization induced by the EEF at the centers of the NC and its shell formed by the ligand environment of NC centers, as well as the electron-vibrational interaction are considered. It should be noted that this model allows to describe both small atomic clusters (whose centers are metal atoms) and large clusters (whose centers are quantum dots). Besides, it gives an opportunity to consider the different variants of the shell of nanocluster (NC): either single (shell covers all NC centers at once) or multiple (shell covers each NC center separately). It is shown that the interaction of a common electron with the vibrational modes of the ligand environment at each of the NC centers, together with the allowance for the polarization effects, leads to a nonlinear electron dynamics in such NCs. The nonlinearity appears explicitly in the differential equations describing the electron subsystem, owing to the exclusion of the intracluster vibrational modes of the ligand environment of the NC centers and the polarization modes describing the charge displacements at each NC center (including its ligands). The analysis of the numerical solutions of the obtained system of differential equations relative to the amplitudes of the probability of detecting an electron at the NC centers for various values of the external and internal model parameters of this system makes it possible to reveal the different regimes in the nonlinear electron localization dynamics, as well as the conditions of switching between them. As the numerical simulation shows,in the tetramer NC (without taking into account the polarization effects) there are three characteristic regimes of the electron localization dynamics. It is important to note that the controlling role of the EEF makes it possible to realize both the regimes with localization and regimes with delocalization of an electron along the direction of action of the EEF. Herewith, the variation of the frequency and amplitude of the EEF controls the duration of complete localization at the NC centers and switches the NC from the state with the localized electron into the state with a delocalized electron. Thus, at the allowance for the polarization effects along with the electron-vibrational interaction in the NC, the control of electron density distribution regimes by the EEF becomes more flexible, since, both the nonlinear response of the NC on the EEF action is taken into account and the number of tunable model parameters is increasing. As a result, of the given model provides ample opportunities to search for new regimes of electron localization in the coated NC of different kind, as well as to realize the aforementionedregimes and to identify the ways of switching between them.