Laser vaporization/rare gas matrix-isolation electron spin resonance studies of PdH sup + sub 2 , PdD sup + sub 2 , PdH, and PdD: Theoretical investigation of PdH sup + sub 2

Journal Article · Thu Mar 01 04:00:00 EST 1990 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.458580· OSTI ID:7166228

Knight, Jr, L B; Cobranchi, S T; Herlong, J; Kirk, T ^[1]; Balasubramanian, K; Das, K K ^[2]

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1. Chemistry Department, Furman University, Greenville, South Carolina 29613 (USA)
2. Department of Chemistry, Arizona State University, Tempe, Arizona 85287-1604 (USA)

The reactive laser vaporization of palladium metal in the presence of H{sub 2}(g) has been used to generate and trap neutral and charged palladium hydride radicals in neon and argon matrices for electron spin resonance investigations. The radicals identified are: {sup 0}PdH{sup +}{sub 2}, {sup 105}PdH{sup +}{sub 2}, {sup 0}PdD{sup +}{sub 2}, {sup 105}PdD{sup +}{sub 2}, {sup 0}PdH, {sup 0}PdD, {sup 105}PdH, and {sup 105}PdD. The electron spin resonance results prove that the H atoms are equivalent in PdH{sup +}{sub 2} but it cannot be determined for certain whether a highly bent {sup 2}{ital A}{sub 1} ground state complex or a linear {sup 2}{Sigma} state is being observed, although the evidence seems to favor the {sup 2}{ital A}{sub 1} state. The observed nuclear hyperfine properties ({ital A} and {ital g} tensors) are best accounted for by assigning the unpaired electron predominantly to 4{ital d}{sup 2}{sub {ital z}}/5{ital s} orbitals on the metal in PdH{sup +}{sub 2} with only about 3% of the spin density on each H atom. Electron spin resonance results for PdH constitute the first observations for a diatomic metal hydride radical trapped in a neon matrix. The magnetic parameters (MHz) for {sup 105}PdH{sup +}{sub 2} in a neon matrix at 4 K are: {ital g}{sub {perpendicular}}=2.568(2); {ital g}{sub {parallel}}{congruent}1.92; {ital A}{sub {perpendicular}}({sup 105}Pd)={minus}713(2); {ital A}{sub {parallel}}({sup 105}Pd)={minus}688(15); {ital A}{sub {perpendicular}}(H)=45(1). Multireference SCF (MCSCF) and configuration interaction (CI) calculations were conducted for PdH{sup +}{sub 2} to calculate the energies and gross population distributions in the lowest-lying electronic states. The lowest of these, the {sup 2}{ital A}{sub 1} state, has a calculated stabilization energy of 9.3 kcal/mol relative to Pd{sup +}(4{ital d}{sup 9})+H{sub 2}.

• OSTI ID: 7166228
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 92:5; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
CATIONS
CHARGED PARTICLES
CONFIGURATION INTERACTION
DEUTERIDES
DEUTERIUM COMPOUNDS
ELECTROMAGNETIC RADIATION
ELECTRON SPIN RESONANCE
ELECTRONIC STRUCTURE
ELEMENTS
EVAPORATION
HYDRIDES
HYDROGEN COMPOUNDS
IONS
LASER RADIATION
MAGNETIC RESONANCE
MATRIX ISOLATION
METALS
MOLECULAR IONS
PALLADIUM
PALLADIUM COMPOUNDS
PALLADIUM HYDRIDES
PHASE TRANSFORMATIONS
PLATINUM METALS
RADIATIONS
RADICALS
RESONANCE
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
ULTRALOW TEMPERATURE