Interaction of 25-keV Electrons with Lattice Vibrations in LiF. Experimental Evidence for Surface Modes of Lattice Vibration

High-energy-resolution monochromator for aberration-corrected scanning transmission electron microscopy/electron energy-loss spectroscopy

“…This type of ability was demonstrated by an instrument built by Boersch, Geiger and co-workers in the 1960s and 1970s (Boersch et al 1966;Schröder & Geiger 1972;Geiger 1981). Their spectrometer system used Wien filters acting on a decelerated beam for both the monochromator and the spectrometer and a primary beam voltage of 25-30 kV.…”

Stimulated excitation electron microscopy and spectroscopy

“…Longstanding experimental data [18] for energy gains and losses for fast electron interaction with optical phonons have been shown [19] to be reasonably consistent with Eq. (1) by considering the effect of the fast electron in driving the upwards and downwards transitions between the energy levels of a simple harmonic oscillator.…”

“…All of this applies in the optical interaction region at small values of q and could certainly be relevant for aloof beam electron spectroscopy since the usual condition for surface modes ε(ω)¼ À1 can be satisfied for a frequency ω lying in the range ω T oωoω L provided the damping is small. The long-wave optical phonon modes at the two surfaces of a thin slab can be strongly coupled and this was indeed observed in the early work with electron spectroscopy [18].…”

Inelastic Electron Scattering in Thin Films at Oblique Incidence

“…Energy gains recently have been observed in the energy spectra of electrons after interaction with lattice vibrations [7]. I n the case of energy losses the angle 6* is located a t @ = TC and in the case of energy gains a t @ = 0.…”