Direct inelastic scattering of N/sub 2/ from Ag(111). I. Rotational populations and alignment

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

OSTI ID:7155923

Sitz, G O; Kummel, A C; Zare, R N

The rotational state populations and the quadrupole and hexadecapole alignment moments of N/sub 2/ scattered off clean Ag(111) are determined by resonance enhanced multiphoton ionization (REMPI). The scattered N/sub 2/ is found to be highly aligned with its rotational angular momentum vector J parallel to the surface. The degree of alignment is found to increase with increasing rotational excitation. We see less than perfect alignment at intermediate J values indicating that the surface is not completely flat. The alignment is relatively insensitive to incident energy, incident angle, or surface temperature T/sub s/. However, the rotational state population distributions show pronounced rainbows for higher incident energy and/or more grazing exit angle. The rotational state distributions are found to depend strongly on the final scattering angle at low T/sub s/; this effect is markedly reduced at higher T/sub s/. Time-of-flight measurements are used to determine the average velocity of the scattered N/sub 2/ as a function of rotational level. It is found that higher rotational excitation correlates with lower average velocity and that the incident molecules lose 20%--30% of their translational energy to the solid. No correlation is found between velocity and alignment. A comparison is made with published results for the NO/Ag(111) system and a variety of theoretical models found in the literature.

• Research Organization: Department of Chemistry, Stanford University, Stanford, California 94305
• OSTI ID: 7155923
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 89:4; 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
ALIGNMENT
ANGULAR MOMENTUM
BEAMS
COLLISIONS
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
IONIZATION
METALS
MOLECULAR BEAMS
MOLECULE COLLISIONS
MULTI-PHOTON PROCESSES
NITROGEN
NONMETALS
PHOTOIONIZATION
RESONANCE
ROTATIONAL STATES
SILVER
SURFACES
TIME-OF-FLIGHT METHOD
TRANSITION ELEMENTS
VELOCITY