Publication

Dynamical charge tensors and infrared spectrum of amorphous SiO2

Alfredo Pasquarello
1997
Journal Articles

Abstract

Using a model structure consisting of a network of corner sharing tetrahedra, we calculate the infrared spectrum of amorphous SiO2 within a first-principles approach and find good agreement with experiment both for the positions and the intensities of the main peaks. In addition to the vibrational properties, this required the dynamical charge tensors, which were obtained applying the recent quantum polarization theory. The relative intensities in the spectrum depend sensitively on the charge tensors and their anisotropic components are crucial to obtain good agreement with experiment. We find that the Born charges can be correlated to the local structural properties.

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https://infoscience.epfl.ch/entities/publication/ba53ffe5-e4a8-4f39-8c87-6c1a32738452

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Alfredo Pasquarello
1997
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/ba53ffe5-e4a8-4f39-8c87-6c1a32738452

About this result

Related concepts (32)

Infrared spectroscopy

Infrared spectroscopy (IR spectroscopy or vibrational spectroscopy) is the measurement of the interaction of infrared radiation with matter by absorption, emission, or reflection. It is used to study and identify chemical substances or functional groups in solid, liquid, or gaseous forms. It can be used to characterize new materials or identify and verify known and unknown samples. The method or technique of infrared spectroscopy is conducted with an instrument called an infrared spectrometer (or spectrophotometer) which produces an infrared spectrum.

Electromagnetic spectrum

The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from below one hertz to above 1025 hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus.

Visible spectrum

The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 380 to about 700 nanometers. In terms of frequency, this corresponds to a band in the vicinity of 400–790 terahertz. These boundaries are not sharply defined and may vary per individual. Under optimal conditions these limits of human perception can extend to 310 nm (ultraviolet) and 1100 nm (near infrared).

Related publications (12)

Dynamical charge tensors and infrared spectrum of amorphous SiO2

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