Infrared lattice vibrational spectra of AgCl, AgBr, and AgI

G. L. Bottger, A. L. Geddes

The infrared transmission spectra of AgCl, AgBr, and AgI have been measured between 400-30 cm-1 at room temperature and at 143°K. Strong absorptions characteristic of the transverse optic modes were found, together with weak subsidiary absorptions arising from multiphonon combinations. The longitudinal optic modes of silver chloride and silver bromide were obtained from the reflection spectra of thin, silver halide films deposited on a silvered substrate. Capacitance measurements were used to determine the static dielectric constant of AgI; ε0=7.0±0.3. For a series of isomorphous I-VII compounds having large reduced masses, approximately linear relations are found between υt2 and the reciprocal reduced masses. The Szigeti relations for effective charge and compressibility were calculated and their significance is discussed.

DOI badge Download BibTeX How to cite Download dataset

Materials
Curve 1
Temperature K: 300 Wavelength Range, µm: 43.9-285 Geometry θ θ' ω: 0° 0° Composition (weight percent), Specifications, and Remarks: Film 1 µm thick; vacuum evaporated onto substrate coated with 0.2 µm film of vacuum deposited silver; data extracted from smooth curve; silvered mirror reference standard.
Curve 1
Temperature K: 300 Wavelength Range, µm: 43.7-294 Geometry θ θ' ω: 0° 0° Composition (weight percent), Specifications, and Remarks: Evaporated film (>1 µm thick) on polyethylene substrate. Film crystalline and highly oriented (200) plane parallel to substrate surface; data extracted from smooth curve.
Curve 2
Temperature K: 143 Wavelength Range, µm: 58.5-286 Geometry θ θ' ω: 0° 0° Composition (weight percent), Specifications, and Remarks: Above specimen and conditions except data corrected for temp dependence of polyethylene transmittance.
Curve 1
Temperature K: 143 Wavelength Range, µm: 43.1-303 Geometry θ θ' ω: 0° 0° Composition (weight percent), Specifications, and Remarks: Evaporated film (~1 µm thick) on polyethylene substrate; film crystalline and highly oriented (200) plane parallel to substrate surface; data extracted from smooth curve; data corrected for temp dependence of polyethylene transmittance.
Curve 2
Temperature K: 300 Wavelength Range, µm: 35.6-333 Geometry θ θ' ω: 0° 0° Composition (weight percent), Specifications, and Remarks: Evaporated film on polyethylene substrate; film crystalline and highly oriented (200) plane parallel to substrate surface; data extracted from smooth curve.
Curve 1
Temperature K: 143 Wavelength Range, µm: 52.6-238 Geometry θ θ': 0° 0° Composition (weight percent), Specifications, and Remarks: Evaporated film (~1 µm thick) on polyethylene substrate; film crystalline and highly oriented (002) plane parallel to substrate surface; data extracted from smooth curve; data corrected for temp dependence of polyethylene transmittance.
Curve 2
Temperature K: 300 Wavelength Range, µm: 52.1-312 Geometry θ θ': 0° 0° Composition (weight percent), Specifications, and Remarks: Above specimen and conditions.