scholarly journals Densities, infrared band strengths, and optical constants of solid methanol

2018 ◽  
Vol 617 ◽  
pp. A116 ◽  
Author(s):  
Ramón Luna ◽  
Germán Molpeceres ◽  
Juan Ortigoso ◽  
Miguel Angel Satorre ◽  
Manuel Domingo ◽  
...  
Keyword(s):  
Infrared Spectra ◽  
Optical Constants ◽  
High Vacuum ◽  
Laboratory Data ◽  
Laser Interferometry ◽  
Infrared Band ◽  
Vacuum Chambers ◽  
Iterative Minimization ◽  
Minimization Procedure ◽  
Different Thickness

Contact. The increasing capabilities of space missions like the James Webb Space Telescope or ground-based observatories like the European Extremely Large Telescope demand high quality laboratory data of species in astrophysical conditions for the interpretation of their findings. Aims. We provide new physical and spectroscopic data of solid methanol that will help to identify this species in astronomical environments. Methods. Ices were grown by vapour deposition in high vacuum chambers. Densities were measured via a cryogenic quartz crystal microbalance and laser interferometry. Absorbance infrared spectra of methanol ices of different thickness were recorded to obtain optical constants using an iterative minimization procedure. Infrared band strengths were determined from infrared spectra and ice densities. Results. Solid methanol densities measured at eight temperatures vary between 0.64 g cm−3 at 20 K and 0.84 g cm−3 at 130 K. The visible refractive index at 633 nm grows from 1.26 to 1.35 in that temperature range. New infrared optical constants and band strengths are given from 650 to 5000 cm−1 (15.4–2.0 μm) at the same eight temperatures. The study was made on ices directly grown at the indicated temperatures, and amorphous and crystalline phases have been recognized. Our optical constants differ from those previously reported in the literature for an ice grown at 10 K and subsequently warmed. The disagreement is due to different ice morphologies. The new infrared band strengths agree with previous literature data when the correct densities are considered.

Brazing Vacuum Ceramic Tubes - A Diffusion Profile in the Joint

2016 ◽  
Vol 367 ◽  
pp. 86-95
Author(s):  
Osmar Roberto Bagnato ◽  
R.F. Francisco ◽  
A.L. Gobbi ◽  
Tatiane Falvo ◽  
P.M. Pimentel
Keyword(s):  
Electron Beam ◽  
High Vacuum ◽  
Diffusion Profile ◽  
Film Deposition ◽  
High Brightness ◽  
Vacuum Chambers ◽  
Ceramic Components ◽  
Synchrotron Light ◽  
The Magnetic Field ◽  
Design Construction

The Sirius Project is an initiative of the Brazilian Synchrotron Light Laboratory - LNLS (CNPEM - MCTI), for the design, construction and operation of a new synchrotron radiation source 3rd generation, with high brightness and energy of the electrons of 3.0 GeV. Among many other components there will be built 80 ceramic cameras embedded in special magnets, whose function is to act to correct the orbit of the electron beam in the storage ring. The ceramic chamber is crucial for this application because this material is transparent to the magnetic field generated in the electro magnet and thus acts directly on the electron beam. The difficulty of these constructive components lies in the fact that, the ceramic components must be attached to metal components will join vacuum chambers that make up the ring, and then must present excellent mechanical and vacuum tight. The process of chemical bonding between the ceramic and metal components is performed by brazing in high vacuum. After brazing, a film is deposited of copper with 7 micrometers thickness. The objective of this paper is to describe the process of film deposition and brazing of copper and the excellent results obtained in the production, mechanical characterization, microstructural and tightness.

scholarly journals The Effect Of Thickness on The Optical Properties Of ZnS

2007 ◽  
Vol 4 (4) ◽  
pp. 647-652
Author(s):  
Baghdad Science Journal
Keyword(s):  
Band Gap ◽  
Room Temperature ◽  
Near Infrared ◽  
High Vacuum ◽  
Ultra Violet ◽  
Infrared Region ◽  
Complex Dielectric Constant ◽  
Film Properties ◽  
Corning Glass ◽  
Different Thickness

Zinc sulfide(ZnS) thin films of different thickness were deposited on corning glass with the substrate kept at room temperature and high vacuum using thermal evaporation technique.the film properties investigated include their absorbance/transmittance/reflectance spectra,band gap,refractive index,extinction coefficient,complex dielectric constant and thickness.The films were found to exhibt high transmittance(59-98%) ,low absorbance and low reflectance in the visible/near infrared region up to 900 nm..However, the absorbance of the films were found to be high in the ultra violet region with peak around 360 nm.The thickness(using optical interference fringes method) of various films thichness(100,200,300,and 400) nm.The band gap measured was found to be in the range (3.52 -3.78 )eV.

Measuring accurate optical constants of uranium minerals for use in optical modeling of infrared spectra

2021 ◽  
Author(s):  
Tanya L. Myers ◽  
Brent M. DeVetter ◽  
Danielle L. Saunders ◽  
Charmayne E. Lonergan ◽  
Michael O. Yokosuk ◽  
...  
Keyword(s):  
Infrared Spectra ◽  
Optical Constants ◽  
Optical Modeling ◽  
Uranium Minerals

scholarly journals Atomic and Molecular Data Needed for Analysis of Infrared Spectra from ISO and Sirtf

1992 ◽  
Vol 9 ◽  
pp. 567-568
Author(s):  
P.F. Bernath
Keyword(s):  
Infrared Spectra ◽  
Laboratory Data ◽  
Molecular Data

AbstractThe satellites ISO and SIRTF are cryogenically-cooled infrared observatories. These telescopes will provide a tremendous increase in sensitivity and will, therefore, require new laboratory data to support their missions. A survey of some of the necessary atomic and moelcular data is presented.

scholarly journals Far-infrared continuum absorption of forsterite and enstatite at low temperatures

2019 ◽  
Vol 625 ◽  
pp. A61
Author(s):  
Harald Mutschke ◽  
Pierre Mohr
Keyword(s):  
Low Temperatures ◽  
Optical Constants ◽  
Laboratory Data ◽  
Measurement Data ◽  
Far Infrared ◽  
Absorption Bands ◽  
Lack Of Information ◽  
Temperature Dependences ◽  
Cold Dust ◽  
Infrared Continuum

Context. The far-infrared continuum opacity of cold dust is an important quantity for the study of debris disks in planetary systems and of protoplanetary disks. Forsterite and enstatite are considered to be the most abundant crystalline dust species in such environments. Aims. The optical constants of these minerals at wavelengths above 80 μm, which govern the opacity, and their temperature dependence are poorly known. Our aim is to fill in this lack of information with new laboratory data. Methods. We present spectroscopic transmission measurements on forsterite and enstatite single crystals of up to 10 mm thickness at wavelengths between 45 and 500 μm and for temperatures down to 10 K. We compare our results to literature data originating from powder transmission and from reflection spectroscopy. Results. The imaginary parts of the refractive indices calculated from the measurements show very strong temperature dependences, which to that extent are not seen in reflection-based data or in powder measurement data. The temperature dependences can be described by a simple theoretical model taking the contributions of single-phonon absorption and phonon difference processes into account. We also observe, for the first time, enstatite absorption bands at 87.5 μm and 116.6 μm wavelengths. Conclusions. The single-crystal optical constants of forsterite and enstatite predict an extremely small submillimeter opacity of crystalline silicate dust at low temperatures, which would make these particles almost invisible in the thermal radiation of cold dust. Thus, it is important to understand why absorption measurements with mineral powders resulted in much higher opacity values.

INFRARED SPECTRA AND OPTICAL CONSTANTS OF ELUSIVE AMORPHOUS METHANE

2015 ◽  
Vol 805 (2) ◽  
pp. L20 ◽  
Author(s):  
Perry A. Gerakines ◽  
Reggie L. Hudson
Keyword(s):  
Infrared Spectra ◽  
Optical Constants

scholarly journals Infrared spectra and optical constants of astronomical ices: II. Ethane and ethylene

Icarus ◽  
2014 ◽  
Vol 243 ◽  
pp. 148-157 ◽  
Author(s):  
R.L. Hudson ◽  
P.A. Gerakines ◽  
M.H. Moore
Keyword(s):  
Infrared Spectra ◽  
Optical Constants

Infrared-Optical Characterization of Metallic Island Films

1997 ◽  
Vol 51 (6) ◽  
pp. 902-904 ◽  
Author(s):  
Arnulf Röseler ◽  
Ernst-Heiner Korte
Keyword(s):  
Infrared Spectra ◽  
Infrared Absorption ◽  
Optical Constants ◽  
Optical Characterization ◽  
Effective Medium ◽  
Island Film ◽  
Surface Enhanced ◽  
Effective Medium Approach ◽  
Island Films

The ellipsometric infrared spectra of a metallic island film indicate its potential for surface-enhanced infrared absorption (SEIRA). Such a film is characterized by unique optical constants, and these can be simulated by using an effective-medium approach.

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