Pietro Ballone

Learn More
A force field model of phosphorus has been developed based on density functional (DF) computations and experimental results, covering low energy forms of local tetrahedral symmetry and more compact (simple cubic) structures that arise with increasing pressure. Rules tailored to DF data for the addition, deletion, and exchange of covalent bonds allow the(More)
Molecular dynamics simulations based on an empirical force field have been carried out to investigate the properties of a zwitter-ionic phospholipid (POPC) bilayer in contact with a water solution of [bmim][Cl], [bmim][PF(6)] and [bmim][Tf(2)N] at concentration c = 0.5 M. The results reveal important and specific interactions of cations and anions with the(More)
Thermal properties of an idealised tetrahedral network model of silica are investigated by Monte Carlo simulations. The interatomic potential consists of anharmonic stretching and bending terms, plus a short range repulsion. The model includes a bond interchange rule similar to the well known Wooten, Winer and Weaire (WWW) algorithm (see Phys. Rev. Lett.,(More)
Neutron reflectometry (NR) measurements were carried out to probe the structure and stability of two model biomembranes consisting of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) phospholipid bilayers hydrated by water solutions of two prototypical room-temperature ionic liquids (RTILs),(More)
The melting behavior of an idealized model giving rise to two-dimensional (2D) structures at low temperature and low density is investigated by Monte Carlo simulations. The system is made of particles carrying a spin of constant length and variable orientation, whose potential energy is the sum of a repulsive spherical pair interaction, and of a spin-spin(More)
Molecular dynamics simulations in the NPT ensemble have been carried out to investigate the effect of two room temperature ionic liquids (RTILs), on stacks of phospholipid bilayers in water. We consider RTIL compounds consisting of chloride ([bmim][Cl]) and hexafluorophosphate ([bmim][PF6]) salts of the 1-buthyl-3-methylimidazolium ([bmim](+)) cation, while(More)
Water solutions of representative ([C4mim][Cl] and [C4mim][Tf2N]) room temperature ionic liquids (ILs) in contact with a neutral lipid bilayer made of cholesterol molecules has been investigated by molecular dynamics simulations based on an empirical force field model. The results show that both ILs display selective adsorption at the water-cholesterol(More)
The glass transition in a quantum Lennard-Jones mixture is investigated by constant-volume path-integral simulations. Particles are assumed to be distinguishable, and the strength of quantum effects is varied by changing variant Planck's over 2pi from zero (the classical case) to one (corresponding to a highly quantum-mechanical regime). Quantum(More)