The Effect of Particle Size on the Heat Capacity of Titanium Dioxide

The heat capacities of four samples of titanium dioxide, differing in particle size, have been measured in the temperature range 12 to 270° K in order to determine the effect of particle size on the specific heat. Contrary to the prediction of existing theories, no effect attributable to a change in particle size has been found in the low-temperature region. On the other hand, above 50° K a pronounced particle-size effect is evident which may be accounted for qualitatively as an effect on the optical modes of vibration of the solid. The complexity of the titanium dioxide crystal structure precludes any quantitative theoretical calculations.