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A study imaged identical regions of partially reduced TiO2(11) surfaces with bridge-bonded oxygen vacancy ([BBO.sub.V]) concentrations of 10% ML using scanning tunneling microscopy (STM) before and after dosing H2O at ambient temperature (300 K). Hydrogen hopping along the [001] direction is observed at ambient temperature, with a strong preference for [OH.sub.B] (10x) hydrogen motion.

The surface photochemistry at 193 nm of tert-butyl nitrite on Ag(111) was investigated by REMPI-TOF and QMS-TOF for coverageEs of 1 SD, 40 SD, and 1 ML. The collisionless component, described using a Gausssian distribution had characteristic translation energy of 0.55 eV higher than for 351-nm but lower than for 248-nm photodissociation.

Nanometer thick layers of Mg metal vapor deposited onto a polycrystalline gold substrate at 22K with and without O2 multilayers are examined. Auger electron spectroscopy and temperature-desorption of N2 are used to estimate the Mg oxidation state and the surface area of the deposits immediately after deposition and following annealing.

On the basis of temperature-programmed desorption and isothermal reaction mass spectrometry, the thermal surface chemistry of trimethyl acetic acid, (CH3)(sub 3)CCOH, dosed onto a well-characterized single-crystal TiO2(110) surface is described. Deprotonation occurs at or below 300 K to form trimethyl acetate, (CH3)(sub 3)CCOO(super -), and hydroxide, OH(super -).

The hydrophilic nature of clean surfaces and the hydrophobic nature of TMA-covered surfaces are revealed by the behavior of H2O on clean and trimethylacetate. The TMA is removed and the wetting behavior of the surface is restored, by the irradiation with the UV light in the presence of Torr of O2.

Adsorbed C(sub 3)H(sub 5) fragments and halogen atoms are generated by the use allyl halides (C(sub 3)H(sub 5)X, X=Cl, Br). Using vibrational and thermal desorption spectroscopies, isomerization and reactivity of sigma-bonded (mew(super 1)) and pie-bonded(mew(super 3)) C(sub 3)H(sub 5) on Cu(100) and Ag(111) are studied.

Phenol surface chemistry is interesting because when its reactions are catalyzed by metals, there can be a number of different initial bond-breaking processes. Using various deuterium-labeled forms, the thermal reaction chemistry is studied of phenol on Pt(111) with temperature-programmed desorption (TPD), high-resolution electron energy loss spectroscopy (HRELLS) and X-ray photoelectron spectroscopy (XPS).

A study was conducted to characterize the thermal chemistry and x-ray and 193 nm photochemistry of C6H4I on Al2O3(0001). The study was carried out in a UHV system supporting a base pressure of 2x10(super -10) Torr. Low-energy excimer laser pulses were incident through a LiF for photolysis. Results indicated that photon irradiation supported dissociation. In addition, the amount of benzene formed increased monotonically with 193 nm irradiation.

The characteristics of 1,3-butadiene (C4H6) adsorbed on Cu(111) are examined with temperature-programmed desorption (TPD) and two-photon photoemission spectroscopy (2PPE). The 2PPE processes of the lowest unoccupied molecular orbital (LUMO) and LUMO+1 of adsorbed butadiene are initiated by substrate-mediated excitation, but that of LUMO+2 is attributed to intramolecular excitation.

Isothermal and temperature programmed desorption mass spectrometry were used for examining the thermal and photochemistry of tert-butyl iodide (t-buI) dosed at 100 K on rutile TiO2(110). Results revealed the occurrence of ultraviolet photochemistry while there were qualitative differences found in the behavior of submonolayers and multilayers.

The preparation and anaerobic ultraviolet photolysis of trimethyl acetate (TMA) on rutile TiO2(110) are examined with an emphasis on reaction paths. Substrates for photolysis are prepared by dosing trimethyl acetic acid at 100, 300 and 550 K.

Reactions of coadsorbed t-butoxy and NO), generated by thermal dissociation of t-butyl nitrite dosed onto Cu(111) are investigated by using time-of-flight mass spectrometry, temperature-programmed desorption and Auger electron spectroscopy. The conclusion states that the proposed high-temperature t-butoxy decomposition is a bimolecular reaction involving transfer of hydrogen without forming chemisorbed H on Cu.

The temperature programmed reaction spectroscopy (TPRS) and reflection-absorption infrared spectroscopy (RAIRS) are employed to investigate the effect of fluorine substitution on the geometrical orientations and the reaction pathways of CH3CH2(a) and CF3CH2(a) on Ag(111). It was seen that the anchoring of CF3CH2(a) by both Ag-C and Ag...F interactions increases the activation energy of CF3CH2(a) migration compared to CH3CH2(a) migration and thus suppresses migratory coupling and facilitates beta-fluorine elimination.

The reflection absorption infrared spectroscopy (RAIRS) and temperature-programmed desorption (TPD) are employed for examining the growth of naphthalene films on Ag(111). The surface infrared spectroscopy selection rule is used for the calculation of the molecular orientation of naphthalene.

The translational, vibrational, and rotational characteristics of nitric oxide, NO, ejected by 351 nm photodissociation of tert-butyl nitrite, (CH3)3CONO, adsorbed on Ag(111) are investigated. It is observed from the study that the vibrational and rotational characteristics of the intermediate transitional component are more complex, and will require simulation and angle-resolved resonance-enhanced multiphoton ionization (REMPI) for fuller eludication.

Issues concerning the thermal chemistry of ClC3H6I on Pt(111) are discussed. For ClC3H6I in contact with Pt, the C-I dissociation arises during heating.

Temperature-programmed desorption, X-ray photoelectron spectroscopy and high-resolution electron energy loss spectroscopy were used to investigate the thermal, electron and photon-induced chemistry of c-C3H6 adsorbed on Pt(111) at 100 K. Monolayer c-C3H6 was found to adsorb without dissociation on Pt(111) at 100 K and desorb molecularly at 144 K. Results also showed that the nonthermal chemistry is activated by either 50 eV of 6.4 eV photon irradiation.