Phosphonate molecular layers on TiO2surfaces

On the formation of warm molecular layers

The levitation of the outer atmospheres of AGB stars by pulsations is proposed as possible mechanism to form " warm molecular layers ". We compare the amounts of CO, H 2 O, CO 2 and SO 2 molecules found in an oxygen-rich dynamical model atmosphere with the values derived from recent ISO observations. In the model, the molecules are present in a layered structure behind shock waves which leads t...

SELF - ASSEMBLY OF PHOSPHONATE MONOLAYERS ON GaAs

Phosphonate utilization by bacteria.

Bacteria able to use at least one of 13 ionic alkylphosphonates of O-alkyl or O,O-dialkyl alkylphosphonates as phosphorus sources were isolated from sewage and soil. Four of these isolates used 2-aminoethylphosphonic acid (AEP) as a sole carbon, nitrogen, and phosphorus source. None of the other phosphonates served as a carbon source for the organisms. One isolate, identified as Pseudomonas put...

Molecular Cloud Formation in Shock-compressed Layers

We investigate the propagation of a shock wave into a warm neutral medium and cold neutral medium by one-dimensional hydrodynamic calculations with detailed treatment of thermal and chemical processes. Our main result shows that thermal instability inside the shock-compressed layer produces a geometrically thin, dense layer in which a large amount of hydrogen molecules is formed. Linear stabili...

Warm molecular layers in protoplanetary disks

We have investigated molecular distributions in protoplanetary disks, adopting a disk model with a temperature gradient in the vertical direction. The model produces sufficiently high abundances of gaseous CO and HCO to account for line observations of T Tauri stars using a sticking probability of unity and without assuming any non-thermal desorption. In regions of radius R ∼> 10 AU, with which...