title: Effect of an external constraint on the photoacoustic spectrum of Nd(2)O(3) powders.
abstract: The photoacoustic spectrum of Nd(2)O(3) powder has been studied to understand the mechanism of the generation of the photoacoustic signal in the constrained and unconstrained powder samples. It is found that the photoacoustic spectrum is qualitatively similar to the transmission spectrum for the unconstrained sample, and the photoacoustic signal intensity is approximately four times less than that in the constrained case. The variation of the photoacoustic signal has been studied by increasing the degree of external constraint on the sample to determine the boundary between constrained and unconstrained situations. The role of air trapped in between powdered microcrystallites in photoacoustic spectrum generation has been also investigated.
authors: K
authors: K
authors: Narayanan
authors: S N
authors: SN
authors: Thakur