*Helmut Hofmann*

- Published in print:
- 2008
- Published Online:
- September 2008
- ISBN:
- 9780198504016
- eISBN:
- 9780191708480
- Item type:
- chapter

- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198504016.003.0006
- Subject:
- Physics, Nuclear and Plasma Physics

This chapter focuses on collective motion of isoscalar nature parameterized by shape variables. The equations of motion are derived from energy conservation as implied by self-consistency. A basic ...
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This chapter focuses on collective motion of isoscalar nature parameterized by shape variables. The equations of motion are derived from energy conservation as implied by self-consistency. A basic ingredient is the variation of the total static energy with deformation, which at finite thermal excitations has to be calculated for constant entropy. Linear response theory is exploited for the dynamics, especially for separating reactive and dissipative forces. Response functions for intrinsic, nucleonic motion are distinguished from those for collective dynamics. The origin of irreversible behavior due to the decay of simple to more complicated nucleonic configurations is described in detail. In practical applications, dressed single particle states are used in their dependence on temperature. The variation of the transport coefficients for inertia and friction with T obtained this way is confronted with that given in various other models, like in the diabatic one, in common RPA, in the random matrix model, or in the liquid drop model and for wall friction. Implications on rotational motion are discussed.Less

This chapter focuses on collective motion of isoscalar nature parameterized by shape variables. The equations of motion are derived from energy conservation as implied by self-consistency. A basic ingredient is the variation of the total static energy with deformation, which at finite thermal excitations has to be calculated for constant entropy. Linear response theory is exploited for the dynamics, especially for separating reactive and dissipative forces. Response functions for intrinsic, nucleonic motion are distinguished from those for collective dynamics. The origin of irreversible behavior due to the decay of simple to more complicated nucleonic configurations is described in detail. In practical applications, dressed single particle states are used in their dependence on temperature. The variation of the transport coefficients for inertia and friction with *T* obtained this way is confronted with that given in various other models, like in the diabatic one, in common RPA, in the random matrix model, or in the liquid drop model and for wall friction. Implications on rotational motion are discussed.

*Helmut Hofmann*

- Published in print:
- 2008
- Published Online:
- September 2008
- ISBN:
- 9780198504016
- eISBN:
- 9780191708480
- Item type:
- chapter

- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198504016.003.0017
- Subject:
- Physics, Nuclear and Plasma Physics

This chapter examines the rate of energy transfer to a system of independent fermions inside a cavity. It is formulated first for the classical wall picture and then for quantum systems by applying ...
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This chapter examines the rate of energy transfer to a system of independent fermions inside a cavity. It is formulated first for the classical wall picture and then for quantum systems by applying basic formulas of linear response theory and allowing for finite frequencies of the external field. It is shown how wall friction can be regained by suitably energy averaging the strength functions involved. Studies of chaotic billiards are briefly reviewed. The formula of wall friction is derived by introducing a macroscopic limit to the microscopic response functions by way of Strutinsky smoothing defined in analogy to the Strutinsky procedure for the static energy.Less

This chapter examines the rate of energy transfer to a system of independent fermions inside a cavity. It is formulated first for the classical wall picture and then for quantum systems by applying basic formulas of linear response theory and allowing for finite frequencies of the external field. It is shown how wall friction can be regained by suitably energy averaging the strength functions involved. Studies of chaotic billiards are briefly reviewed. The formula of wall friction is derived by introducing a macroscopic limit to the microscopic response functions by way of Strutinsky smoothing defined in analogy to the Strutinsky procedure for the static energy.

*Helmut Hofmann*

- Published in print:
- 2008
- Published Online:
- September 2008
- ISBN:
- 9780198504016
- eISBN:
- 9780191708480
- Item type:
- chapter

- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198504016.003.0016
- Subject:
- Physics, Nuclear and Plasma Physics

The stability of metal clusters exhibits shell effects similar to that of nuclei. This chapter reviews how this feature is treated in the jellium model. The main focus is on optical properties ...
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The stability of metal clusters exhibits shell effects similar to that of nuclei. This chapter reviews how this feature is treated in the jellium model. The main focus is on optical properties described by the dielectric function, which is analyzed in greater detail, first for the Drude-Lorentz model then for a fully quantal treatment. With increasing volume of the clusters, only bulk properties typical for a metal are important. For smaller systems, quantum size effects come into play. This effect is studied, reporting on microscopic calculations within the jellium model. Of special interest is the damping width, for which finite values are obtained even at small frequencies if the quantal electronic states are treated as being quasi-continuous. This mechanism is often associated with Landau damping known to conserve entropy. The problem related to this fact is examined, together with the analogous one of wall friction in finite nuclei.Less

The stability of metal clusters exhibits shell effects similar to that of nuclei. This chapter reviews how this feature is treated in the jellium model. The main focus is on optical properties described by the dielectric function, which is analyzed in greater detail, first for the Drude-Lorentz model then for a fully quantal treatment. With increasing volume of the clusters, only bulk properties typical for a metal are important. For smaller systems, quantum size effects come into play. This effect is studied, reporting on microscopic calculations within the jellium model. Of special interest is the damping width, for which finite values are obtained even at small frequencies if the quantal electronic states are treated as being quasi-continuous. This mechanism is often associated with Landau damping known to conserve entropy. The problem related to this fact is examined, together with the analogous one of wall friction in finite nuclei.