addition to the “classical” modes observed in the rutile structure, two other regions shown
Raman activity for nanoparticles. The Raman bands in the low-frequency region are
attributed to acoustic modes associated with the vibration of the individual nanoparticle as a
whole. The high-frequency region is activated by surface disorder. A detailed analysis of
these regions and the changes in the normal modes of SnO 2 are presented as a function …