Topic
Absorption (logic)
About: Absorption (logic) is a research topic. Over the lifetime, 5733 publications have been published within this topic receiving 236302 citations.
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TL;DR: The absorption of SrTi${\mathrm{O}}_{3}$ below the fundamental edge shows, near liquid-nitrogen temperature, an oscillatory behavior, for which an explanation is proposed in terms of indirect transitions, centered around 3.46 eV as discussed by the authors.
Abstract: The absorption of SrTi${\mathrm{O}}_{3}$ below the fundamental edge shows, near liquid-nitrogen temperature, an oscillatory behavior, for which an explanation is proposed in terms of indirect transitions ${\ensuremath{\Gamma}}_{15}\ensuremath{\rightarrow}{X}_{3}$, centered around 3.27 eV and involving a 51-meV LO phonon. There is no evidence of excitonic effects. The first direct transition is probably ${X}_{{5}^{\ensuremath{'}}}\ensuremath{\rightarrow}{X}_{3}$ and is located at \ensuremath{\sim}3.46 eV. Broadening effects mask the indirect structure at higher temperatures where the absorption curves gradually evolve into normal Urbach tailing.
157 citations
TL;DR: Femtosecond midinfrared spectroscopy of water (heavy water) after two photon excitation at 9 eV provides clear evidence for two short-lived precursors of the hydrated electron preceding the well-known "wet electron".
Abstract: Femtosecond midinfrared spectroscopy of water (heavy water) after two photon excitation at 9 eV provides clear evidence for two short-lived precursors of the hydrated electron preceding the well-known ``wet electron.'' The measured first intermediate with peak absorption at 2.9 $(4.1)\ensuremath{\mu}\mathrm{m}$ is proposed to represent an $\mathrm{O}(\mathrm{H},\mathrm{D}):{e}^{\ensuremath{-}}$ complex. The subsequent solvation proceeds via ${e}^{\ensuremath{-}}:[(\mathrm{H},\mathrm{D}{)}_{2}\mathrm{O}{]}_{n}$ complexes at approximately 1.6 $(2.0)\ensuremath{\mu}\mathrm{m}$ in the electronic ground state, involving an increasing number of water molecules during the first 200 fs and followed by the wet electron.
156 citations
TL;DR: A totally nonempirical relativistic cluster calculation of transition-metal x-ray-absorption near-edge structure including configuration interaction has been performed in this article, and a remarkable predictive power of this calculation has been demonstrated for three contrasting materials with different d-electron numbers and different coordination numbers.
Abstract: A totally nonempirical relativistic cluster calculation of transition-metal ${L}_{2,3}$-edge x-ray-absorption near-edge structure including configuration interaction has been performed. A remarkable predictive power of this calculation has been demonstrated for three contrasting materials with different d-electron numbers and different coordination numbers $({\mathrm{SrTiO}}_{3},$ NiO, and ${\mathrm{CaF}}_{2})$ by excellent reproduction of both the absolute peak energies and their relative intensities without any empirical parameters.
156 citations
TL;DR: In this article, the laser-induced breakdown of a high-quality mirror consisting of alternating 4-4 layers of a single 500-nm thin film was studied with amplified and unamplified femtosecond pulses.
Abstract: Laser-induced breakdown of a high-quality mirror consisting of alternating $\ensuremath{\lambda}/4$ layers of ${\mathrm{Ta}}_{2}{\mathrm{O}}_{5}$ and ${\mathrm{SiO}}_{2}$ and a single 500-nm thin film of ${\mathrm{Ta}}_{2}{\mathrm{O}}_{5}$ were studied with amplified and unamplified femtosecond pulses. The experimental data can be fitted with a model taking into account multiphoton absorption, impact ionization, and local intensity enhancements due to interference effects in the films. Incubation effects are observed when the coatings are damaged with multiple pulses from a femtosecond oscillator. The results indicate that state of the art, high-quality thin films show a damage behavior that is similar to bulk materials. Defects and impurities play a negligible role.
156 citations
TL;DR: In this paper, a spectrometer with a grating of the echelette type was used in mapping the absorption spectrum of ammonia gas in the region from 1 to 4 cm wave-length.
Abstract: A spectrometer, with a grating of the echelette type, was used in mapping the absorption spectrum of ammonia gas in the region from 1 to 4 cm wave-length. To accomplish this, it became necessary to produce electromagnetic waves of shorter wave-length than had been produced before by vacuum tubes. Oscillators of the magnetron type were used as the source of the continuous short wave radiation. The center of the absorption band had been predicted to be at 1.5 cm wave-length. The maximum absorption was found to occur at 1.25 cm. This shift is explained by the unsymmetrical nature of the line. The constants in a theoretical formula for the absorption coefficient have been determined. These constants involve an effective collision diameter of the molecule, and lead to the value $\ensuremath{\sigma}=8.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ cm. The total intensity of the line was found to be 10\ifmmode\times\else\texttimes\fi{}${10}^{7}$ ${\mathrm{cm}}^{\ensuremath{-}1}$ ${\mathrm{sec}.}^{\ensuremath{-}1}$.
156 citations