Search results for "Spectra"
showing 10 items of 3542 documents
Study of exotic decay of Cs isotope close to the proton drip line
2020
6 pags., 6 figs. -- 27th International Nuclear Physics Conference (INPC2019) 29 July - 2 August 2019, Glasgow, UK
Line Shape Measurement and Modelling for Plasma Diagnostics
2014
In this paper we discuss different methods of narrow spectral line shape measurements for a wide spectral range by means of high-resolution spectrometers such as the Fabry-Perot spectrometer, Zeeman spectrometer and Fourier transform spectrometer as well as a theoretical model for spectral line shape modelling and solving of the inverse task based on Tikhonov's regularization method. Special attention is devoted to the line shape measurements for the optically thin light sources filled with Hg, Ar, Xe, Kr for their use in high precision analysers for detection of heavy metals and benzene.
Comparison of ZrO2:Y nanocrystals and macroscopic single crystal luminescence
2007
The luminescence spectra of a tetragonally structured ZrO2:Y single crystal and nanocrystals were compared. It was found that the number of luminescence centers contributed to the spectra. The excitation of luminescence within the band gap region led to different luminescence spectra for the single crystal and nanocrystal samples, whereas recombinative luminescence spectra were the same for both samples. The origin of this difference is that in the nanocrystals, even under excitation within the band gap, charge carriers were created. Zirconium- oxygen complexes distorted by intrinsic defects were proposed to be the luminescence centres responsible for the wide luminescence band observed.
Computer simulation and experimental studies of the N I 3p 2S o 1/2 − 3d 2P1/2 spectral line Stark broadening
2017
A computer simulation method, dedicated to lines, which energy levels are influenced only by the quadratic Stark effect, is introduced and tested in this paper. The simulated profiles of the well isolated N I line 3p 2So 1/2 – 3d 2P1/2 are compared with experimental ones.
Investigation of the hyperfine structure of weak atomic Vanadium lines by means of Fourier transform spectroscopy
2015
In continuation of our work on the investigation of the hyperfine structure (HFS) of atomic vanadium, we analyzed weak spectral lines in a Fourier transform spectrum that have not been investigated up to now. The main objective of this work was the determination of the magnetic dipole HFS constant A of the energy level at 15 103.784 cm−1, which was the only energy level with unknown A value up to the energy of 28 000 cm−1. Additionally, other gaps in the data of magnetic dipole HFS could be filled in. The spectrum of vanadium–argon plasma in a hollow cathode lamp is recorded in the spectral range from 12 500 to 26 000 cm−1 or 800 to 380 nm, respectively. The HFS of 42 weak atomic vanadium l…
High Resolution Study of the v1 + 2v2 −v2 and 2v2 + v3 − v2 ”Hot” Bands and Ro-Vibrational Re-Analysis of the v1 + v2/v2 + v3/3v3 Poliad of the SO2 M…
2010
The main goal of the present study was to analyse rotational stuctures of two excited vibrational states, (120) and (021). Because both the band, v1+2v2 and 2v2+v3 one are extremally weak, a special efforts were faired to record very weak hot bands, v1+2v2−v2 and 2v2+v3−v2.Both of those bands are located in the region of considerably more stronger combinational bands, v1 + v2 and v2 + v3. On that reason, as the first step of analysis, we made assignments of transitions belonging to these v1 + v2 and v2 + v3 bands. As the result of analysis, we were able to assign three times more transitions to the bands v1 + v2 and v2 + v3 than it was known in the before literature. After "cleaning" the ex…
Influencia del efecto de la humedad del suelo en la emisividad del infrarrojo térmico
2007
La influencia del efecto de la humedad del suelo en la emisividad del infrarrojo térmico es un hecho conocido pero poco estudiado en el pasado. Se ha diseñado un experimento para calcular la dependencia de la emisividad respecto a la humedad del suelo. Han sido seleccionadas seis muestras de horizontes superficiales de diferentes tipos de suelos mediterráneos. Su emisividad se ha medido con diferentes contenidos de agua de suelo, utilizando la variante de dos tapas del método de caja, mientras que el método gravimétrico ha sido seleccionado para obtener la humedad del suelo. Como resultado de esto, el estudio muestra que la emisividad aumenta significativamente cuando el contenido de agua s…
Combinatorial Identification of Hydrides in a Ligated Ag40 Nanocluster with Noncompact Metal Core
2019
No formation of bulk silver hydride has been reported. Until very recently, only a few silver nanoclusters containing hydrides have been successfully prepared. However, due to the lack of effective techniques and also poor stability of hydride-containing Ag nanoclusters, the identification of hydrides' location within Ag nanoclusters is challenging and not yet achieved, although some successes have been reported on clusters of several Ag atoms. In this work, we report a detailed structural and spectroscopic characterization of the [Ag40(DMBT)24(PPh3)8H12]2+ (Ag40H12) cluster (DMBT = 2,4-dimethylbenzenethiol). The metal framework consists of three concentric shells of Ag8@Ag24@Ag8, which can…
Hydrogen bond studies on n-pentanol and 2-methyl-2-butanol by Raman spectroscopy
1986
Polarized Raman spectra of n-pentanol and its isomer 2-methyl-2-butanol are obtained in the liquid phase near the melting points and at superheated temperatures. The measurements are performed in the intramolecular O-H stretching region. Our analysis of the Raman data provides an interpretation of the spectral features in terms of symmetric O-H bands, originated by various degrees of intermolecular coupling, for which mechanism is different for the two isomers. Temperature dependence of the spectra is also discussed in terms of available structural and dynamical models for these H-bonded liquids.
Structural characterization of β-2′-pyridylaminocrotonoyl-2-pyridylamide by ESI-MS, NMR, single crystal X-ray analysis and ab initio methods
2003
Abstract In contradiction with earlier reports 1H, 13C and 15N NMR spectra show that β-2′-pyridylaminocrotonoyl-2-pyridylamide is the only form present in chloroform solution. According to the X-ray data the same tautomer exists also in the crystal state. The studied amide has a dimeric form where the monomer molecules are held together by two intermolecular hydrogen bonds. The NMR spectral data show that there is also an intramolecular hydrogen bond in each monomer subunit. The dilution experiments and variable-temperature 1H NMR runs show that β-2′-pyridylaminocrotonoyl-2-pyridylamide tends to form the dimers also in chloroform solution at higher concentrations. The ESI-TOF MS measurement…