Ab initio study of vibrational and optical properties of stable ZnmOn(m + n = 2 to 5) nanoclusters P. S. Yadav, D. K. Pandey, S. Agrawal and B. K. Agrawal Eur. Phys. J. Plus, 130 4 (2015) 60 Published online: 02 April 2015 DOI: 10.1140/epjp/i2015-15060-2