Shape, Structural, and Energetic Effects on the Cohesive Energy and Melting Point of Nanocrystals

Abstract

A nonlinear, lattice type-sensitive model, free of any adjustable parameter, has been developed to account for the shape and size dependency of the cohesive energy of free-standing nanocrystals (nanoparticles, -wires, and -films). In this model, the effects of the averaged structural and energetic properties of the surface and the volume of nanocrystals along with the first and second nearest-neighbor atomic interactions have been taken into consideration and gathered in a new parameter named as the surface-to-volume energy contribution ratio. This model has been compared to the experimental data of the cohesive energy of W and Mo nanoparticles, and the melting points of Au, Pb, Al, and Sn nanoparticles and Pb and In nanofilms. Moreover, the model has been corrected to account for the effect of substrate on the melting point of substrate-supported Sn nanodisks. It has been found that the present model has generally a good agreement with those experimental data measured by different techniques under different experimental conditions.

The effects of the size of nanocrystalline materials on their thermodynamic and mechanical properties

“… Effects of size on the mechanical and thermodynamic properties of nanocrystalline materials. Size dependence of (A) heat capacity C m [ 46 - 48 ] and (B) Young’s modulus Y for Ag [ 43 , 45 - 47 ], (C) Debye temperature Θ D , [ 49 , 19 - 52 ] and (D) diffusion activation energy Q d for Au [ 53 , 19 , 50 - 52 ]. Solid lines refer to parameters calculated from Equation 9 (our model prediction).…”

Melting and freezing temperatures of confined Bi nanoparticles over a wide size range

“…The transition temperatures, such as the melting and freezing temperatures, of nanoparticles depend on their size (Takagi, 1954;Peppiatt, 1975;Allen et al, 1986;Kofman et al, 1990) and shape (Qi & Wang, 2004;Safaei, 2010;Zayed & Elsayed-Ali, 2005). The classical technique to determine ISSN 1600-5767 # 2017 International Union of Crystallography transition temperatures experimentally is based on thermal analysis.…”

A Modified Universal Rose-Smith-Francisco-Ferrante Cohesive Energy Function for FCC Transition Spherical Metallic Nanoparticles

“…Building a full physically acceptable theoretical energy function that regenerates both bulk and nano-scale experimental predictions have become an increasingly important matter. Up-to-date, several effective potential energy functions (PEF) and models tried to simulate the interatomic interaction within nanoparticles, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] or nanotubes [17][18][19] with some failures and a number of conditional successes based on many assumptions that undermine the predicted results. Many researchers were able to use semi-empirical PEFs with adjustable parameters.…”