Ground state structures, electronic and optical properties of medium-sized Nan+ (n = 9, 15, 21, 26, 31, 36, 41, 50 and 59) clusters from ab initio genetic algorithmXiaoming Huang, Linwei Sai, Xue Jiang and Jijun ZhaoEur. Phys. J. D, 67 2 (2013) 43DOI: https://doi.org/10.1140/epjd/e2013-30539-2