A new, more flexible definition of fuzzy Voronoi cells is proposed as a computationally efficient alternative to Bader's Quantum Theory of Atoms in Molecules (QTAIM) partitioning of the physical space for large-scale routine calculations. The new fuzzy scheme provides atomic charges, delocalization indices, and molecular energy components very close to those obtained using QTAIM. The method is flexible enough to either ignore the presence of spurious non-nuclear attractors or to readily incorporate them by introducing additional fuzzy Voronoi cells

Financial help has been furnished by the Spanish MICINN Project No. CTQ2011-23441/BQU, the FEDER UNGI08-4E-003, and the Generalitat de Catalunya SGR528 grants. Support from the Xarxa de Referencia en Quimica Teorica i Computacional is also acknowledged. E. R.-C. acknowledges support from the Spanish FPU program (Grant No. AP2008-01231)