Significant nonlinear-optical switching capacity in atomic clusters built from silicon and lithium: A combined ab initio and density functional study. - Panaghiotis Karamanis; Nicolás Otero; Claude Pouchan; Juan José Torres; William Tiznado; Aggelos Avramopoulos; Manthos G. Papadopoulos (J. Comput. Chem., 2014)