Landau damping and wall dissipation in large metal clusters

Journal Article · Wed Jul 01 04:00:00 EDT 1992 · Annals of Physics (New York); (United States)

DOI:https://doi.org/10.1016/0003-4916(92)90340-R· OSTI ID:6908814

Yannouleas, C ^[1]; Broglia, R A ^[2]

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1. Virginia Commonwealth Univ., Richmond, VA (United States) Istituto Nazionale di Fisica Nucleare, Milan (Italy)
2. Universita di Milano, Milano (Italy) Istituto Nazionale di Fisica Nucleare, Milan (Italy) Niels Bohr Institute, Copenhagen (Denmark)

The discrete-matrix random phase approximation (RPA) is used to describe the photoabsorption of large, spherical metal clusters. In this limit, the single-peak, classical Mie regime is valid and the matrix-RPA equations can be solved analytically. The RPA yields a closed formula for the width, [Gamma], of this peak due to Landau damping. This width is inversely proportional to the radius R of the cluster, in agreement with experimental observations for large silver and gold clusters embedded in a host medium. The RPA proportionality coefficient is unequivocally determined, and the reasons for the uncertainty in its value arising from disagreements among previous theoretical approaches are discussed. [Gamma]=[lambda]g([h bar][Omega][sub sp]/[var epsilon][sub F])[bar [upsilon]]/R, where [lambda] is the multipolarity of the plasma vibration, [Omega][sub sp] is the frequency of the surface plasmon, and [var epsilon][sub F] is the Fermi energy of the conduction electrons. The function g varies from unity to zero as the frequency of the surface plasmon increases from zero to infinity. The frequency dependence of g for a spherical shape is identical to that of a cubical boundary. [bar [upsilon]]=(3[upsilon][sub F]/4)(1 + ([pi][sup 2]/6)(T/[var epsilon][sub F])[sup 2]) is the average speed of a Fermi gas at temperature T. This result indicates a very small dependence on temperature, in agreement with the observation. A classical interpretation of this result is proposed based on the similarities with the one-body, wall-dissipation theory familiar from nuclear physics. According to this interpretation, the surface of the cluster is viewed as a moving wall whose interaction with the conduction electrons mimicks the multipole transitions induced by the electric field of the plasmon. This interpretation expresses [Gamma] as the ratio, [Gamma] = y/B, of a surface friction coefficient, y, over an inertia mass, B. 81 refs., 4 figs.

• OSTI ID: 6908814
• Journal Information: Annals of Physics (New York); (United States), Journal Name: Annals of Physics (New York); (United States) Vol. 217:1; ISSN 0003-4916; ISSN APNYA6
• Country of Publication: United States
• Language: English

Related Subjects

664000* -- Atomic & Molecular Physics-- (1992-)
665000 -- Physics of Condensed Matter-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMIC CLUSTERS
DAMPING
ELEMENTS
ENERGY-LEVEL TRANSITIONS
FERMI GAS
FLUIDS
FREQUENCY DEPENDENCE
GASES
GOLD
LANDAU DAMPING
METALS
MULTIPOLE TRANSITIONS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PLASMONS
QUASI PARTICLES
RANDOM PHASE APPROXIMATION
SILVER
TRANSITION ELEMENTS