Simulation of proton transport

While the fundamental laws governing all natural phenomena are simple, most condensed matter systems are not. Often the behavior of macroscopic systems is determined by complex, collective phenomena at the microscopic level and chaotic motion is the rule rather than the exception. Few systems exemplify this complexity arising from seemingly simple components better than liquid water. Despite its ubiquity and overwhelming importance for life on earth, this fascinating liquid remains a challenge for the scientist. In particular, the role of water in numerous chemical and biological processes is only partially understood. The multiple role played by water molecules and the wide ranges of length, energy and time scales involved in their description complicate the study of such processes. Research in Prof. Dellago`s group is directed towards using computer simulations to understand the microscopic dynamics of processes occurring in complex condensed phases such as water. Running on today`s fast computers, such simulations can be used as a "virtual microscope" to follow the motion of many molecules interacting in a complicated way with each other providing us with detailed knowledge of complex materials on a molecular level. The research program developed in the present proposal is centered around the computer simulation of proton transport in hydrogen-bonded systems. Proton conduction is of crucial importance for a variety of processes in nature and technology ranging from ATP synthesis in living cells and enzymatic catalysis to electrical power generation in hydrogen fuel cells and chlorine chemistry on stratospheric ice particles involved in polar ozone depletion. But despite the fundamental importance of proton transfer in aqueous systems, this process remains poorly understood. As for most of water`s remarkable kinetic and thermodynamic properties, hydrogen bonds play an important role in this process. Such hydrogen bonds provide routes for proton transfer from one water molecule to another. As protons are shuttled between neighboring water molecules, hydrogen bonds are transformed into chemical bonds and vice versa. To accurately describe and simulate this process, powerful but computationally expensive simulation and analysis techniques, some of which are being developed in our group, have to be applied. Using state of the art high performance computer equipment we will use such methods to study proton transport in liquid water and glycerol (another hydrogen-bonded liquid), in hexagonal ice and in carbon nanotube membranes. Detailed dynamical information gleaned from our simulations will provide a better understanding of how water participates in many fundamental chemical, biological and technological processes.

While the fundamental laws governing all natural phenomena are simple, most condensed matter systems are not. Often the behavior of macroscopic systems is determined by complex, collective phenomena at the microscopic level and chaotic motion is the rule rather than the exception. Few systems exemplify this complexity arising from seemingly simple components better than liquid water. Despite its ubiquity and overwhelming importance for life on earth, this fascinating liquid remains a challenge for the scientist. In particular, the role of water in numerous chemical and biological processes is only partially understood. The multiple role played by water molecules and the wide ranges of length, energy and time scales involved in their description complicate the study of such processes. Research in Prof. Dellago`s group is directed towards using computer simulations to understand the microscopic dynamics of processes occurring in complex condensed phases such as water. Running on today`s fast computers, such simulations can be used as a "virtual microscope" to follow the motion of many molecules interacting in a complicated way with each other providing us with detailed knowledge of complex materials on a molecular level. The research program developed in the present proposal is centered around the computer simulation of proton transport in hydrogen-bonded systems. Proton conduction is of crucial importance for a variety of processes in nature and technology ranging from ATP synthesis in living cells and enzymatic catalysis to electrical power generation in hydrogen fuel cells and chlorine chemistry on stratospheric ice particles involved in polar ozone depletion. But despite the fundamental importance of proton transfer in aqueous systems, this process remains poorly understood. As for most of water`s remarkable kinetic and thermodynamic properties, hydrogen bonds play an important role in this process. Such hydrogen bonds provide routes for proton transfer from one water molecule to another. As protons are shuttled between neighboring water molecules, hydrogen bonds are transformed into chemical bonds and vice versa. To accurately describe and simulate this process, powerful but computationally expensive simulation and analysis techniques, some of which are being developed in our group, have to be applied. Using state of the art high performance computer equipment we will use such methods to study proton transport in liquid water and glycerol (another hydrogen-bonded liquid), in hexagonal ice and in carbon nanotube membranes. Detailed dynamical information gleaned from our simulations will provide a better understanding of how water participates in many fundamental chemical, biological and technological processes.