AI Article Synopsis
- A new method using inelastic neutron scattering (INS) has been developed to determine the isotopic properties of substances by calculating beta-factors of single-element solids.
- INS experiments were conducted on nanodiamonds of varying sizes and bulk diamond, enabling the measurement of their heat capacities and beta-factors for the first time.
- The study reveals that smaller nanodiamonds exhibit higher heat capacities and lower beta-factors compared to bulk diamond, with surface impurities and phonon confinement playing significant roles in these size-dependent effects.
Article Abstract
A new experimental method for the determination of equilibrium isotopic properties of substances based on inelastic neutron scattering (INS) is proposed. We present a mathematical formalism, which allows the calculation of the beta-factor of single-element solids based on INS-derived Phonon Density of States (PDOS). PDOS data for nanodiamonds of widely different sizes and of macroscopic diamond were determined from inelastic neutron scattering experiments. This allowed the determination of heat capacities and, for the first time, β-factors of the diamond nanoparticles. We demonstrate a considerable size-dependent increase of the heat capacities and decrease of the beta-factors for nanodiamonds relative to bulk diamond. Contributions of surface impurities/phases and phonon confinement to the size effects are evaluated. Applications in the formation of diamond nanoparticles in nature are briefly discussed.
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| http://dx.doi.org/10.1039/d0cp02032j | DOI Listing |
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