Otto Stern (Sohrau 1888 – Berkeley 1969) Nobel Laureate 1943
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Otto Stern (Sohrau 1888 – Berkeley 1969) Nobel Laureate 1943
description
Otto Stern (Sohrau 1888 – Berkeley 1969) Nobel Laureate 1943. Otto Stern, O.R. Frisch, I. Estermann (Hamburg, 1929-1933). He . NaCl(001). - PowerPoint PPT Presentation
Transcript of Otto Stern (Sohrau 1888 – Berkeley 1969) Nobel Laureate 1943
Otto Stern (Sohrau 1888 – Berkeley 1969) Nobel Laureate 1943
Otto Stern, O.R. Frisch, I. Estermann (Hamburg, 1929-1933)
He
NaCl(001)
[meV]542.4
][Å2[Å] 1
iEk
),(2GG K
),K(k
nma
kkk ifz
“These experiments are of interest not only because of their confirmation of the predictions of quantum mechanics, but also because they introduce the possibility of applying atom diffraction to investigations of the atomic constitution
of surfaces.” (T. M. Johnson, Phys. Rev. 37 (1931) 847).
Bound-state resonances
Frisch-Stern (1933)
J. E. Lennard-Jones and A. F. Devonshire, Nature 137 (1936) 1069.
I00
Gas – Surface Interactions:
- energy transfer
- sticking (adsorption)
INELASTIC SCATTERING
INELASTIC RESONANCES
)()(1)-()( QQQQ
212vifvvifvQvfi
iz
f
ff
)(
-EEn-EEnk
dΩdEd
vk
uF
Lattice vibrations (phonons)
)exp()( zAzV o
),(e4
2 sinh2sinhsinhsinh
2/1
22
22
i-Wpp
pppp
pp
if
if
if
i
f
fi
QF
/βπkp/βπkp fzfizi ,
J.M. Jackson and N.F. Mott, Proc. Roy. Soc. A 137 (1932) 703: Quantum DWBA
L.D. Landau, Phys. Z. Sowjet. 8 (1935) 489.B.L. Bonch-Bruevich, Usp. Fiz. Nauka 40 (1950) 369 Classical
Rarified Gas Dynamics
Supersonic Molecular Beams
Supersonic He-atom beam sourcesTime-of-flight spectroscopy
High-resolution diffraction
J. P. Toennies: HUGO (MPI-SF, Goettingen)
Angular distributions
Diffraction
Bound state resonances, etc.
Time of Flight (TOF) Inelastic scattering
Phonons
via the mechanical action (Pauli repulsion) on the electron density
Forces between atoms
Forces between ions and electrons (electron-phonon interaction)
& electronic susceptibility
Phonon dispersion curves
Surface waves
Lord Rayleigh (1887)
Irpinia 1980 (Polo Sismico Alberto Gabriele, FCCSEM Erice)
Surface phonons 1: from 3D lattice to slab
Surface phonons 2: from 2D monolayer to slab
TOF spectrum
Energy-transfer spectrum
scan curves for 90° geometry
HAS versus theory
theory: Green Function surface dynamics + DWBA
scattering theory
LiF(001)
NaF(001)
Metals: Skin & Bones
1D conductor
Peierls instability
electron-hole excitations
HAS hole-electron pairs!
The Helium-3 Spin-Echo Spectroscopy
P. Fouquet, A.P. Jardine, S. Dworski, G. Alexandrowicz, W. Allison and J. Ellis
"Thermal energy 3He spin-echo spectrometer for ultrahigh resolution surface dynamics measurements“ Rev. Sci. Inst. 76, 053109 (2005).
Parameter Value
Total scattering angle 44.4 degrees
3He Angular Resolution 0.1 degree
Nominal beam energy 8 meV
Measured beam intensity 1e14 atoms/second
Beam diameter at target 2 mm
Energy resolution (QE peak width) 20 neV
Scattering chamber base pressure 2e-10 mbar
Sample manipulator 6 axis, titanium
Sample manipulator resolution 0.003 degrees
Sample heating Radiation / E-beam
Sample cooling Liquid Nitrogen or Helium
Sample temperature range 55 K - >1200 K
The Cavendish He3 Spin-Echo Apparatus
A first test for He3 Spin-Echo:
Bound states of He3 on LiF(001)
A.P. Jardine, S. Dworski, P. Fouquet, G. Alexandrowicz, G.Y.H. Lee, D.J. Riley, J. Ellis, W. Allison, "Ultrahigh resolution spin-echo measurement of surface potential energy landscapes", Science 304, 1790-1793 (2004).
back to Frisch & Stern!
PMCS substratecluster beamtime of flight
mass spectrometer
quartz MB
2000 l/s diff. pump
500 l/s turbo pump
700 l/s diff. pump
He line
sample manipulator
target cluster assembled film
to pulsed power supply
SOURCE CHAMBERDEPOSITION CHAMBER TOF-MS
CHAMBER
SUPERSONIC CLUSTER BEAM DEPOSITION at the Department of Physics, University of Milano
Grenoble - 9
Giorgio Benedek J. Peter Toennies
Helium Atom Scattering Spectroscopy of Surface Phonons
Springer-VerlagBerlin Heidelberg New York 2007
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