Search

Kinetics of benzene adsorption on crystalline silica films supported on Mo(112) and Mo(112)-p(1x3)-O were studied employing temperature programmed desorption (TPD) and Auger electron spectroscopy (AES). Benzene adsorbed molecularly on both surfaces according to TPD and AES. Strong chemisorption is evident on oxidized Mo(112) with two different binding sites while physisorption is seen on crystalline silica films with a single adsorption site. Support effects of benzene adsorption on silica films were also studied. Silica films are not transparent to benzene adsorption and no support effects are evident according to TPD results., Mindika T Nayakasinghe * (G), Nilushni Sivapragasam, and Uwe Burghaus Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58105 Support: RCA Internal Funding-Seed award Corresponding Author's Email: [...]

Adsorption of DNA into acid-prepared mesoporous silica (APMS) is studied by evaluating the relationships between cation identity and concentration, pore diameter, and surface area with respect to DNA adsorption. Confocal scanning laser microscopy reveals that fluorescently labeled DNA molecules are able to diffuse into the pores of APMS-34.

A new phenomenon named as 'lens' effect is reported in the directed-assembly process of nanowires on self-assembled monolayer (SAM) patterns. In this process, the adsorption of the nanowires is focused in the nanoscale regions at the center of microscale SAM patterns with gradient surface molecular density just like an optical lens focuses light.

The study stated that a vibrational spectroscopy was used to examine the in situ adsorption of CO+NO to form CO(sub 2)N(sub 2)O and N(sub 2) on a Pd(III) model catalyst under high-pressure conditions. The results provide direct evidence for the formation of an isocyanate C-N(O) species on Pd- sites under reaction conditions (500-600K).

The initial stages of water adsorption on Au surfaces using low-temperature ultrahigh vacuum (UHV) scanning tunneling microscopy (STM) measurements, are reported. STM images of an Au surface showed the usual herringbone pattern before exposure to water. After exposure to water, many small islands were evident on the terraces and step edges, evincing planar, and not three-dimensional contours.

The stereochemistry of surfaces exposed to trans-and cis-1,2-dideuterioethylene was investigated using Fourier-transform infrared (FTIR) spectroscopy. Ultrahigh vacuum conditions were used based on a multiple internal reflection geometry. The samples included on-axis Si(001) and off-axis Si(001). Major differences in infrared spectra obtained from the reactants show that ethylene interaction with Si(001) is stereospecific, and almost completely stereoselective.

A polymer film remains effectively thin, even when it is hundreds of atom layers thick, because of the deposition of deuterated polystyrene on the silicon surface. The adsorption of a large number of chains on the surface hinders other chains and results in slow diffusion of polymer chains. Thin film polymers find application in electronics, controlling the alignment of liquid crystals, and high-temperature polymers for insulating layers in integrated circuits.

Zeolitic protons catalyze methanol to give dimethyl ether in an associative mechanism by two pathways. The first path involves adsorption of a methanol molecules at the zeolite acidic site followed by dehydration. The methoxy species then reacts with the second methanol adsorbed on the surface to give DME. Thus the dehydration of the first methanol is the rate determining step. The second pathway, which has a lower activation barrier than path 1, involves coadsorption of two methanol molecules on the acidic and basic sites of zeolite. One of the methanol molecules undergoes a rotation to yield DME.

Self-assembled monolayers, (SAM), of alkanethiolates on gold have tri(propylene sulfoxide) groups that prevent the non-specific adsorption of proteins on a surface. These groups have a repeating hydrophilic unit, a unit that is solvated and can form hydrogen bonds, and a conformationally flexible oligomer like propylene sulfoxide group, (-CH2CH2CH2S(O)-). The oligomer is biocompatible and can be employed for interactions with biological systems.

The optical adsorption spectra of gold nanorods were modeled by the Link and co-workers and they derived a simple relationship equation between the adsorption. It was found that the function of the gold nanorods was wavelength-dependent.

Absorption and reaction of acetylene on a hexagonally reconstructed (5*20)-Pt(100) surface and two ordered Sn/Pt(100) alloy surfaces are investigated. This investigation used temperature programmed desorption spectrometry (TPD), Auger electron spectroscopy (AES) low energy electron diffraction (LEED) and X-ray photoelectron spectroscopy (XPS).

Adsorption isotherms for Na-mordenite and H-mordenite are reported at a range of temperatures with gas adsorptives above their critical temperature.