Confinement effects on the vibrational properties of III-V and II-VI   nanoclusters
  We present a first-principles study of the confinement effects on the vibrational properties of thousand atoms (radii up to 16.2 {\AA}) colloidal III-V and II-VI nanoclusters. We describe how the molecular-type vibrations, such as surface--optical, surface--acoustic and coherent acoustic modes, coexist and interact with bulk-type vibrations, such as longitudinal and transverse acoustic and optical modes. We link vibrational properties to structural changes induced by the surface and highlight the qualitative difference between III-Vs and II-VIs. We describe the size dependence of the vibrations and find good agreement for Raman shifts and for the frequency of coherent acoustic modes with experiments. 
Peng Han and Gabriel Bester
cond-mat.mes-hall cond-mat.mtrl-sci