Molecular beam photoionization and gas-surface scattering

Technical Report · Sat Sep 01 04:00:00 EDT 1979

DOI:https://doi.org/10.2172/5857262· OSTI ID:5857262

Ceyer, S T

The energetics of the ethylene ion-molecule reactions was investigated in more detail than previously possible in two body collision experiments by photoionization of the neutral van der Waals ethylene dimer. The stability of the (C/sub 2/H/sub 4/)/sup +/C/sub 2/H/sub 4/ ion-molecule collision complex has been determined to be 18.2 +- 0.5 kcal. The highest potential barriers along the reaction coordinate for decomposition of this collision complex into C/sub 4/H/sub 7//sup +/ + H and C/sub 3/H/sub 5//sup +/ + CH/sub 3/ have been determined to be 0 +- 1.5 and 8.7 +- 1.5 kcal. In a similar manner, the energetics of the solvated ethylene dimer ion was investigated by the photoionization of the ethylene trimer. The absolute proton affinity of NH/sub 3/ (203.6 +- 1.3 kcal/mole) and the proton solvation energies by more than one NH/sub 3/ have been determined by molecular beam photoionization. In addition, the NH/sub 3//sup +/-NH/sub 3/ interaction energy (0.79 +- 0.05 eV) was measured by photoionization of the neutral van der Waals dimer. These experiments have shown that photoionization of van der Waals clusters is a very powerful method of determining the energetics of gas phase proton solvation. The scattering of helium atomic beams from a high Miller index platinum surface that exhibits ordered, periodic steps on the atomic scale to probe the effect of atomic steps on the scattering distribution is explored. Rainbow scattering is observed when the step edges are perpendicular to the incident helium atoms. The design, construction and operation of a beam-surface scattering apparatus are described. The first data obtained in this apparatus are presented and the interesting dynamical aspects of the oxidation of D, D/sub 2/ and CO are discussed. 75 references.

• Research Organization: California Univ., Berkeley (USA). Lawrence Berkeley Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5857262
• Report Number(s): LBL-9838
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ALKENES
AMMONIA
ANGULAR DISTRIBUTION
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
BINDING ENERGY
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
COLLISIONS
CRYOGENIC FLUIDS
DATA
DATA FORMS
DEUTERIUM
DISTRIBUTION
ELASTIC SCATTERING
ELEMENTS
ENERGY
ENERGY DEPENDENCE
ETHYLENE
EXPERIMENTAL DATA
FLUIDS
GRAPHS
HELIUM
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
INFORMATION
ION COLLISIONS
ION-MOLECULE COLLISIONS
IONIZATION
ISOLATED VALUES
ISOTOPES
KINETICS
LIGHT NUCLEI
METALS
MOLECULE COLLISIONS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHOTOIONIZATION
PLATINUM
PLATINUM METALS
POTENTIAL ENERGY
POTENTIAL SCATTERING
RARE GASES
REACTION KINETICS
SCATTERING
STABILITY
STABLE ISOTOPES
TRANSITION ELEMENTS
VAN DER WAALS FORCES