Spectrum

MIR normalized biconical reflectance spectrum of Calcite powder, unsieved

Title
MIR normalized biconical reflectance spectrum of Calcite powder, unsieved
DOI
10.26302/SSHADE/EXPERIMENT_BS_20220803_001
Data reference
Schmitt, Bernard; Leclef, Apolline; Montagnac, Gilles (2021): Calcite: Vis-NIR and Mid-IR diffuse reflectance, MIR specular reflectance and Raman spectra of powders and blocks. SSHADE/DRIMS (OSUG Data Center). Dataset/Spectral Data. https://doi.org/10.26302/SSHADE/EXPERIMENT_BS_20220803_001
Experiment type
laboratory measurement
Type
normalized reflectance
Intensity unit
no unit
Reference position
7500.0 $cm^{-1}$
Comments
a correction factor of 0.99 needs to be applied to this normalized spectrum to best fit the absolute photometry of the equivalent VNIR spectrum in the 2400-3100 and 3750-4500 $cm^{-1}$ (3.12-4.15 & 1.85-2.65 µm) ranges, but there is no perfect fit over all the common spectral range, especially in-between the 2 above sub-ranges, as 2 different samples of the same matter (Calcite-DG-01_pwd) have been used (different compaction, adsorbed amount of $H_2O$, ...) and due to inaccurate photometry of the FTIR (MIR) measurements above about 4500 $cm^{-1}$.
Instrument
Brucker Vertex 70 #2 – reflection Mid-IR
Sample holder
cylindrical raw aluminium sample holders of various sizes for powders
Standard medium
vacuum
Observation mode
spectrum
Spectral range type(s)
NIR, MIR
Valid spectral range(s)
Min - Max ($cm^{-1}$) Sampling ($cm^{-1}$) Resolution ($cm^{-1}$) Position accuracy ($cm^{-1}$) Absorption edge
#1 550.0 - 7500.0 0.482 1.0 0.1
Observation geometry
biconical
Observation mode
fixed angles
Incidence angle
0.0°
Emergence angle
30.0°
Azimuth angle
0.0°
Phase angle
30.0°
Illumination
Observation
Comments
some wavelength dependent polarization
Observation mode
single spot
Resolutions
4.0 ${\pm}$ 0.5 $mm$
Name
Calcite powder (unsieved)
Comments
Contain a small amount of Fe
Experiment
Calcite: Vis-NIR and Mid-IR diffuse reflectance, MIR specular reflectance and Raman spectra of powders and blocks
Date begin
2022-05-04
Release date
2024-06-09 15:59:28 UTC+0000
Version (Date)
#1 (2024-06-09 15:59:28 UTC+0000, Updated: 2024-07-10 17:41:11 UTC+0000)
History
Date Mode Version Status Comments
2022-08-19 19:39:50 UTC+0000 first import #1 valid version
Analysis
raw biconical reflectance spectrum calibrated in relative reflectance with "matte gold plate" measured under same geometry assuming flat spectral reflectance over the whole 7500-540 $cm^{-1}$ range, and normalized to 1 at 7500 $cm^{-1}$ . Residual water vapor lines (between 1750-1400, 3900-3550, 5500-5200 $cm^{-1}$ ) and $CO_2$ vapor lines (around 630-700 and 2360-2300 $cm^{-1}$ ) have been partly corrected by dividing by scaled $H_2O$ and $CO_2$ vapor transmission spectra measured at same resolution and sampling, or interpolated ($CO_2$ around 2340 $cm^{-1}$ ).
Quality flag
4
Validator(s)