National Center for Computational Sciences

It has been a long standing objective in the chemical and catalysis sciences to find a novel energy source in the release and control of the hydrogen in water. When hydrogen-bonded liquids are in solution, researchers must calculate two kinds of energy that occur at the : the energy of motion of the atoms (kinetic energy) and the energy these atoms will have when they interact with one another (the interaction potential). While calculating the kinetic energy is straightforward, calculating the interaction potential is very difficult. So researchers use a “smart” program and massive computational powerto calculate these fundamental processes for them from first principles. Chris Mundy and a team from Pacific Northwest National Laboratory (PNNL) is using 4 million hours on Oak Ridge National Laboratory’s petascale computer Jaguar to calculate transfer of the free energy of hydronium (H30+)—an extremely reactive ion of hydrogen that is readily dissolved in water—from solution to the interface. The team is using three software programs, CP2K, a program that performs atomistic and molecular simulations; CPMD code, which is designed for molecular dynamics; and MCR, which is used to study liquid-vapor interfaces. The DOE considers explorations of the molecular nature of the liquid water interface to be discovery science; the study of positively charged hydronium and negatively charged hydroxide at the air/water interface will have high impact in atmospheric chemistry and in the understanding of aqueous phase systems.