Dissociative scattering of 1. 5--4. 5 keV N/sup +//sub 2/ and N/sup +/ on gold and graphite surfaces

Journal Article · Thu Sep 15 04:00:00 EDT 1988 · J. Chem. Phys.; (United States)

OSTI ID:6967008

Sass, C S; Rabalais, J W

Scattering of molecular nitrogen ions in the 1.5--4.5 keV range from gold and graphite surfaces results in a small fraction of surviving molecules and molecular ions in addition to atoms and atomic ions resulting from dissociation. The kinetic energy (E/sub k/ ) distributions of scattered N/sup +//sub 2/ and N/sup +/ ions have been measured directly by means of an electrostatic sector analyzer (ESA) and the velocity distributions of the scattered N/sub 2/ and N neutrals plus ions have been measured by time-of-flight (TOF) techniques. Scattered ion fractions were determined from the TOF measurements. The relative E/sub k/ distributions of the scattered atomic ions indicate that dissociation from excited repulsive electronic states which are populated during the collision dominate the mechanism, rather than purely vibrational or rotational excitation from the X /sup 2/..sigma../sup +//sub g/ ground state of N/sup +//sub 2/ . The excited dissociative C /sup 2/..sigma../sup +//sub u/ and D /sup 2/Pi/sub u/ states of N/sup +//sub 2/ are accessible by Franck--Condon transitions from the X/sup 2/..sigma../sup +//sub g/ state. The data are consistent with a mechanism in which these two dissociative states contribute their repulsive energy to the large relative E/sub k/ distributions of the scattered N/sup +/ ions. The electronic excitation occurs via electron promotion during the scattering collision through the Fano--Lichten mechanism.

• Research Organization: Department of Chemistry, University of Houston, Houston, Texas 77004
• OSTI ID: 6967008
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 89:6; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

656003* -- Condensed Matter Physics-- Interactions between Beams & Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMIC IONS
BEAMS
CARBON
CHARGED PARTICLES
COLLISIONS
DISSOCIATION
DISTRIBUTION
ELEMENTAL MINERALS
ELEMENTS
ENERGY
ENERGY RANGE
GOLD
GRAPHITE
ION BEAMS
ION COLLISIONS
IONS
KEV RANGE
KEV RANGE 01-10
KINETIC ENERGY
METALS
MINERALS
MOLECULAR IONS
NITROGEN IONS
NONMETALS
SURFACES
TIME-OF-FLIGHT METHOD
TRANSITION ELEMENTS
VELOCITY