The thermal properties of bimetallic clusters
碩士 === 國立中央大學 === 物理研究所 === 94 === The brownian-type molecular dynamics has been applied to study the effect of temperature on bimetallic clusters. Two specific issues are addressed. The first issue concerns the use of different ensembles in simulation of finite systems. We make a semiquantitative c...
| Main Authors: | , |
|---|---|
| Other Authors: | |
| Format: | Others |
| Language: | en_US |
| Published: |
2006
|
| Online Access: | http://ndltd.ncl.edu.tw/handle/c888cf |
| Summary: | 碩士 === 國立中央大學 === 物理研究所 === 94 === The brownian-type molecular dynamics has been
applied to study the effect of temperature on bimetallic clusters. Two specific issues are addressed. The first issue concerns the use of different ensembles in simulation of finite
systems. We make a semiquantitative comparison between the specific heat Cv and the root-mean-squared relative bond length fluctuation
parameter δ of bimetallic clusters obtained in the present canonical ensemble simulations and those by the microcanonical ensemble. Systematic
discongruity in the simulation results alludes to the inherent difference of the two ensembles for finite-sized systems. The second issue concerns the generally incomplete agreement in temperature dependences for Cv and δ. Here we make an analysis of the time evolution of the
instantaneous relative bond length fluctuation rij, where the ith and jth are two atoms judiciously selected from the cluster. We give temporal evidence that the permutational isomer transition between ij-atoms in the bimetallic cluster which contributes to δ is due to these two atoms transiting to a higher-lying isomer state and this temporal behavior
can be inferred from rij. The rij(t) therefore dictates the detail of the microscopic change in time and provides us with a means for understanding the incompatibility of δ and Cv
|
|---|