Date of Original Version
We use fluctuational electrodynamics to determine spectral emissivity and van der Waals contribution to surface energy for various spherical shapes, such as a sphere, a bubble, a spherical shell and a coated sphere, in a homogeneous and isotropic medium. The dyadic Green's function formalism of radiative energy and fluctuation-induced van der Waals stress for different spherical configurations have been developed. We show (1) emission spectra of micro and nano-sized single and coated spheres display several emissivity sharp peaks as the size of object reduces, and (2) surface energy becomes size dependent due to van der Waals phenomena when size of object is reduced to a nanoscopic length scale.
Zheng, Y., & Ghanekar, A. (2015). Radiative energy and momentum transfer for various spherical shapes: a single sphere, a bubble, a spherical shell and a coated sphere. Journal of Applied Physics, 117: 064314.
Available at: http://dx.doi.org/10.1063/1.4907913