Ab initio calculations for the absorption spectra and polarizabilities of small sulfur clusters

• 来源期刊: 中国物理（英文版）
• 关键词: absorption spectra threshold absorption polarizability HOMO-LUMO gaps
• 年，卷（期）: 2007,（3）
• 页码范围: 700-706
• 页数: 7页
• 语种: 英文

摘要

Absorption spectra for Sn clusters(n=2...8) are calculated using an adiabatic time-dependent density functional formalism within the local density approximation (LDA) .We compare the calculated spectra with those computed using a simple LDA approach.The time-dependent LDA (TDLDA) spectra display a significant blue shift with respect to the LDA spectra.The calculated spectra present a variety of features that can be used for comparison with future experimental investigations.We also obtain a significant threshold absorption,which can distinguish between different ground states of the sulfur clusters.In addition,the polarizabilities of the clusters are calculated by using the higherorder finite-difference pseudopotential density functional method in real space.We find that the polarizabilities of the constant.The computed polarizabilities per atom tend to decrease with increasing cluster size.The polarizabilities are closely related to the HOMO-LUMO gaps and the geometrical configurations.