We have calculated heat capacity of TiO 2 nanoparticles in three stable polymorphs by applying size and surface effects on heat capacity of the bulk structure. The size and surface corrections were imposed on the acoustic and optical bulk phonons, separately. The model used in the present work is a simple modification of the model proposed by Wang et al. We applied the modified model to obtain the specific heat capacity of 10-100 nm TiO 2 nanoparticles. A very good consistency is observed between the computational and experimental data. Based on the modified model, particles with sizes larger than 70 nm behave like bulk structure. In addition, the heat capacity of particles smaller than 15 nm become independent from their structure details while demonstrating a drastic increase.

No abstract

No abstract