FDE-vdW: A van der Waals Inclusive Subsystem Density-Functional Theory

We present a formally exact van der Waals inclusive electronic structure theory, called FDE-vdW, based on the Frozen Density Embedding formulation of subsystem Density-Functional Theory. In subsystem DFT, the energy functional is composed of subsystem additive and non-additive terms. We show that an appropriate definition of the long-range correlation energy is given by the value of the non-additive correlation functional. This functional is evaluated using the Fluctuation-Dissipation Theorem aided by a formally exact decomposition of the response functions into subsystem contributions. FDE-vdW is derived in detail and several approximate schemes are proposed, which lead to practical implementations of the method. We show that FDE-vdW is Casimir-Polder consistent, i.e. it reduces to the generalized Casimir-Polder formula for asymptotic inter-subsystems separations. Pilot calculations of binding energies of 13 weakly bound complexes singled out from the S22 set show a dramatic improvement upon semilocal subsystem DFT, provided that an appropriate exchange functional is employed. The convergence of FDE-vdW with basis set size is discussed, as well as its dependence on the choice of associated density functional approximant

Patrizi veneziani artisti nel Settecento: l’altro Marcello, Alessandro, pittore e incisore

A profile of the Venetian patrician Alessandro Marcello as a painter and engraver is outlined here for the first time. Alessandro, brother of the more famous Benedetto, was also a musician and a poet (he joined the Academy of Arcadia), as well as a scientist and mathematician: an emblem of the typical Eighteenth-century amateur, open to the most varied experiences. Antonio Maria Zanetti drawed an amusing caricature of him. Alessandro was friend with Rosalba Carriera, who painted his portrait; he executed some frescoes in the church of the Magdalene and in his palace (here illustrated), a series of paintings with Putti engaging in playful scenes, documented by archival findings also published here. A medal with his portrait is indicative of the fame he had achieved in the early Eighteenth century: most interestingly, it presents, on the reverse, a tree with different flowers and fruits, a sign of its interests in various fields