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QUANTUM ESPRESSO is an integrated suite of computer codes for electronic-structure calculations and materials modeling, based on density-functional theory, plane waves, and pseudopotentials (norm-conserving, ultrasoft, and projector-augmented wave). The acronym ESPRESSO stands for opEn Source Package for Research in Electronic Structure, Simulation, and(More)
Using a density-functional approach, we study the dielectric permittivity across interfaces at the atomic scale. Focusing on the static and high-frequency permittivities of SiO2 films on silicon, for oxide thicknesses from 12 A down to the atomic scale, we find a departure from bulk values in accord with experiment. A classical three-layer model accounts(More)
OBJECTIVE This study aimed to evaluate laparoscopic dismembered pyeloplasty compared with open surgery and to determine whether the morbidity and outcome rates are different in each of these techniques. We report our 10-year experience with open and laparoscopic pyeloplasty at one istitution. METHODS From February 1999 to October 2010, 49 patients with(More)
Organohalide lead perovskites have revolutionized the scenario of emerging photovoltaic technologies. The prototype MAPbI3 perovskite (MA = CH3NH3(+)) has dominated the field, despite only harvesting photons above 750 nm (∼1.6 eV). Intensive research efforts are being devoted to find new perovskites with red-shifted absorption onset, along with good charge(More)
Hybrid AMX3 perovskites (A = Cs, CH3NH3; M = Sn, Pb; X = halide) have revolutionized the scenario of emerging photovoltaic technologies, with very recent results demonstrating 15% efficient solar cells. The CH3NH3PbI3/MAPb(I(1-x)Cl(x))3 perovskites have dominated the field, while the similar CH3NH3SnI3 has not been exploited for photovoltaic applications.(More)
We treat homogeneous electric fields within density functional calculations with periodic boundary conditions. A nonlocal energy functional depending on the applied field is used within an ab initio molecular dynamics scheme. The reliability of the method is demonstrated in the case of bulk MgO for the Born effective charges, and the high- and low-frequency(More)
The recursion method of Haydock, Heine and Kelly is a powerful tool for calculating diagonal matrix elements of the resolvent of quantum-mechanical Hamiltonian operators by elegantly expressing them in terms of continued fractions. In this paper we extend the recursion method to off-diagonal matrix elements of general (possibly non-Hermitian) operators and(More)
The electronic energy levels of some representative isolated and oxide-supported organic dyes, relevant for photovoltaic applications, are investigated using many-body perturbation theory within the GW approximation. We consider a set of all-organic dyes (denominated L0, L2, L3, and L4) featuring the same donor and anchor groups and differing for the linker(More)
Using a first-principles approach, we calculate Raman spectra for a model structure of vitreous silica. We develop a perturbational method for calculating the dielectric tensor in an ultrasoft pseudopotential scheme and obtain Raman coupling tensors by finite differences with respect to atomic displacements. For frequencies below 1000 cm(-1), the(More)
INTRODUCTION We present a refinement to our original technique in MtF gender reassignment surgery. Our goal was to construct a neoclitoris, which is wet and covered with urethral neoprepuce. Since 1995 more than 300 transgender MtF patients have been operated at our institution. Our refinement has been applied to 12 cases and showed both excellent(More)