Using the field ion microscope as a flow reactor the catalytic oxidation of hydrogen by O2 on Pt has been studied by the ToF coincidence technique. The "imaging ions" consist mainly of H30+. less H20+ and to some extent field and coverage sensitive 02+ species. The product ion spectrum qualitatively coincides with that of pure water field desorbed at 300 K. On the oxygen side of the H2/02/Pt sy...

Surface affinity of hydro-nium was explored using umbrella sampling molecular dynamics simulations with a refined polarizable potential. The polarizable interaction potential of H(3)O(+) was reparametrized against accurate ab initio calculations for geometries including a water molecule approaching the Eigen cation from its oxygen side. Although there is no true hydrogen bonding with H(3)O(+) a...

D-glucono-1,5-lactone differs from D-glucopyranose only in that it has a C = O group instead of CHOH group at carbon atom number one. The molecule therefore possesses an intact 3,4 alpha-glycol group and is sweet. However, it autohydrolyses in water solution at room temperature, forming D-gluconic acid and D-glucono-1,4-lactone. As the solution pH falls it becomes sweet-sour and eventually almo...

Solution-gated graphene transistors were developed recently for use in pH sensor applications. The device operation is understood to rely on the capability of hydronium and hydroxide ions in solution to change the electrical properties of graphene. However, hydronium and hydroxide ions are accompanied by other ionic species in a typical acidic or basic solution and, therefore, the roles of thes...

We define BioScapeL, a stochastic pi-calculus in 3D-space. A novel aspect of BioScapeL is that entities have programmable locations. The programmer can specify a particular location where to place an entity, or a location relative to the current location of the entity. The motivation for the extension comes from the need to describe the evolution of populations of biochemical species in space, ...

Surface sensitive synchrotron X-ray scattering studies were performed to obtain the distribution of monovalent ions next to a highly charged interface. A lipid phosphate (dihexadecyl hydrogen-phosphate) was spread as a monolayer at the air-water interface to control surface charge density. Using anomalous reflectivity off and at the L3 Cs+ resonance, we provide spatial counterion (Cs+) distribu...

Epoxydiols are produced in the gas phase from the photo-oxidation of isoprene in the absence of significant mixing ratios of nitrogen oxides (NO(x)). The reactive uptake of these compounds onto acidic aerosols has been shown to produce secondary organic aerosol (SOA). To better characterize the fate of isoprene epoxydiols in the aerosol phase, the kinetics and products of the acid-catalyzed rin...

The recent demonstration of enhanced surface anion concentrations for aqueous electrolyte solutions strongly contrasts current textbook descriptions. Small cations are still expected to be repelled from the surface, but recent simulations predict that hydronium (H3O+) cations are instead preferentially adsorbed at the interface. Here we describe a comparative second harmonic generation (SHG) st...

Autoionization of water which gives rise to its pH is one of the key properties of aqueous systems. Surfaces of water and aqueous electrolyte solutions are traditionally viewed as devoid of inorganic ions; however, recent molecular simulations and spectroscopic experiments show the presence of certain ions including hydronium in the topmost layer. This raises the question of what is the pH (def...