Ab initio study of new sp3 silicon and germanium allotropes predicted from the zeolite topologies Vladimir A. Saleev, Alexandra V. Shipilova, Davide M. Proserpio and Giuseppe Fadda Eur. Phys. J. B, 90 8 (2017) 150 Published online: 09 August 2017 DOI: 10.1140/epjb/e2017-80152-2