Obtaining the complex optical constants n and k via quantitative absorption measurements in KBr pellets

The possible IR- and Raman-active phonons of α-boron. β-boron, and boron carbide have been obtained by group theoretical methods. Reflectivity and absorption measurements in the spectral range from 10 to 1450 cm-1 and a classical dispersion analysis yield the entire spectra of the anisotropic optical constants in the lattice vibration range of β-boron and beyond. From the reflectivity spectrum of boron carbide the resonance frequencies of the phonons and estimated values of their other characteristic values have been derived. The absorption spectrum of amorphous boron has been included in the discussion. - Certain frequency ranges can be attributed to vibrations of the icosahedra split in the crystal field. Single vibrations with E∥c displaced to higher frequencies are attributted to the central atoms in the unit cells of β-boron and boron carbide. The phonon shift depending on temperature can be described by the Grüneisen shift. Three- and four-phonon processes are necessary to describe the temperature dependent damping constants of the lattice vibrations.

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Cavity ring‐down spectroscopy for quantitative absorption measurements

The Journal of Chemical Physics ◽

10.1063/1.468647 ◽

1995 ◽

Vol 102 (7) ◽

pp. 2708-2717 ◽

Cited By ~ 327

Author(s):

Piotr Zalicki ◽

Richard N. Zare

Keyword(s):

Cavity Ring Down Spectroscopy ◽

Quantitative Absorption ◽

Absorption Measurements ◽

Cavity Ring Down

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Quantitative Absorption Measurements Using Cavity-Ringdown Spectroscopy with Pulsed Lasers

ACS Symposium Series - Cavity-Ringdown Spectroscopy ◽

10.1021/bk-1999-0720.ch007 ◽

1999 ◽

pp. 93-105 ◽

Cited By ~ 4

Author(s):

J. Patrick Looney ◽

Joseph T. Hodges ◽

Roger D. van Zee

Keyword(s):

Cavity Ringdown Spectroscopy ◽

Pulsed Lasers ◽

Cavity Ringdown ◽

Quantitative Absorption ◽

Absorption Measurements

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Development of 200kV ultrahigh-resolution analytical electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152513 ◽

1989 ◽

Vol 47 ◽

pp. 108-109

Author(s):

T. Kaneyama ◽

M. Naruse ◽

Y. Ishida ◽

M. Kersker

Keyword(s):

Electron Microscope ◽

Optical Constants ◽

Materials Science ◽

Objective Lens ◽

The Finite Element Method ◽

Ultrahigh Resolution ◽

Analytical Electron ◽

Analytical Electron Microscope ◽

Characteristic Features ◽

Better Than

In the field of materials science, the importance of the ultrahigh resolution analytical electron microscope (UHRAEM) is increasing. A new UHRAEM which provides a resolution of better than 0.2 nm and allows analysis of a few nm areas has been developed. [Fig. 1 shows the external view] The followings are some characteristic features of the UHRAEM.Objective lens (OL)Two types of OL polepieces (URP for ±10' specimen tilt and ARP for ±30' tilt) have been developed. The optical constants shown in the table on the next page are figures calculated by the finite element method. However, Cs was experimentally confirmed by two methods (namely, Beam Tilt method and Krivanek method) as 0.45 ∼ 0.50 mm for URP and as 0.9 ∼ 1.0 mm for ARP, respectively. Fig. 2 shows an optical diffractogram obtained from a micrograph of amorphous carbon with URP under the Scherzer defocus condition. It demonstrates a resolution of 0.19 nm and a Cs smaller than 0.5 mm.

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