TRANSVERSALITY OF OBJECTIVES – The scientific programme of this project is structures in three sublines and ten different objectives. All the suggested tasks involve, completely or partially at least, empirical observations; they require specific models tailored to describe the systems of interest; they have a strong computational component due to their very complex nature; and they develop as far as possible formal and analytical studies. In what follows, we present brief descriptions of the objectives:
(1) Study of quantum effects in static and dynamic properties of molecules and solids. The thermodynamic and kinetic properties of light atoms, especially hydrogen, cannot be properly described without taking into account quantum effects. Our goal is to develop a simulation code able to perform this calculation, and to apply it to the study of the following systems: Water and ice; diffusion of light defects in semiconductors and graphene; phase diagram of neon and the diffusion of hydrogen in a matrix of disordered nano-spheres. Apart from quantum nuclear effects we will study some electronic properties that can only be described through the quantum formalism, among them ultra-small semiconductors, organic structures, and graphene. This objective shares techniques with objectives 2, 3, and 4.
(2) Study of the properties of complex fluids, polymers, and liquid crystals. We will study the structural and thermodynamic properties of some complex fluids and their mixtures. Simulations on dendrimers (nano particles with application in catalysis), drug transport and lubricants will be performed. The smectic phase in polydisperse solutions of platelets will be studied from a theoretical viewpoint; we will develop a hybrid method to study defects in liquid crystals. This objective shares techniques with objectives 1, 3, and 4; its results are of interest for the study of soft biological matter (objective 5); conceptually, it is close to the study of heterogeneous populations (objective 6) here from a static viewpoint.
(3) Study of the behaviour of confined systems and interfaces. Here we will study the properties of non-homogeneous fluids. When a fluid is confined inside a material or in contact with a solid wall, it presents non-homogeneous profiles that try to minimize its free energy. Interfaces also appear when the fluid coexists in two phases (liquid and vapour, for instance). We will focus in the study of phases and phase transitions, and in self-assembly phenomena. Confinement modifies these effects, increasing or inhibiting them in different situations, even changing their very nature (as order in a phase transition). The techniques to be used go from the design of models and their formal analysis to experiments, and include computational simulation that will require developing specific, system-dependent methods. Recently, the UAM and ICMM groups have established the link the CWT and the microscopic level by means of the Intrinsic Sampling Method (ISM), which constitutes an excellent tool to extract relevant information regarding the microscopic structure of interfaces from molecular simulations. The ISM allows for an identification of those particles pertaining to the liquid and those to the vapour phase for each sample configuration along a simulation run. Thus it is possible to define an intrinsic surface separating vapour and liquid phases. In the preceding research program (MOSSNOHO-CM) this methodology was successfully applied to the study of liquid-vapour interfaces in metals, water, and recently water-hydrofobic liquid interfaces. In the present program, the ISM methodology will be a key point to enhance the collaboration among various groups, in order to tackle different problems. We will focus in the study of thermal fluctuations at interfaces (liquid-vapour, liquid-liquid, membranes, etc.). This objective shares techniques with objectives 1, 2, 4, and 5. The presence of non-trivial fluctuations and phase transitions is observed in almost all systems studied in this project, especially in systems tacked in objective 1 (water), 5 (membrane formation), 6 (quasispecies), and 9 (dynamics on complex networks).
