What is diffuse reflectance in UV-VIS?
Since light cannot penetrate opaque (solid) samples, it is reflected on the surface of the samples. As shown in the figure, incident light reflected symmetrically with respect to the normal line is called “specular reflection,” while incident light scattered in different directions is called “diffuse reflection.”
What is diffuse reflectance spectroscopy used for?
Diffuse reflectance spectroscopy is a well-established technique for studying the spectral characteristics of opaque solid samples, based on the principle that not only does light reflected from the material come from the surface (specular reflection) but some is reflected internally (diffuse reflectance).
What is diffuse reflectance on what types of samples is it used?
DRIFTS is commonly used for the analysis of both organic and inorganic samples that can be ground into a fine powder (less than 10 microns) and mixed in a powder matrix such as potassium bromide (KBr).
What is the difference between UV VIS and UV DRS?
UV-VIS most often refers to absorption spectroscopy, measured by transmission, whereas DRS specifically refers to diffuse reflection spectroscopy. Normally, the former is used for solutions/suspensions or thin films, whereas the latter is used for solids – optically rough films or powders.
How does diffuse reflectance infrared Fourier transform spectroscopy work?
DRIFTS analysis of powders is conducted by focusing infrared light onto the powder (sometimes diluted in a non absorbing matrix) and the scattered light is collected and relayed to the IR detector. DRIFTS FTIR can also be applied to other materials with matte or dull surfaces such as fabrics and filled plastics.
Where is diffused reflection used?
Diffuse reflectance spectroscopy can be used to determine the absorption spectra of powdered samples in cases where transmission spectroscopy is not feasible. This applies to UV-Vis-NIR spectroscopy or mid-infrared spectroscopy.
Which of these compounds is used as the reference in diffuse reflectance UV Visible Spectroscopy?
The reference material is BaSO4. It has a reflectance of 100% in the visible region. However, in the UV region it is showing a reflectance between 105 and 110%… how is this possible?
What is differential reflectance?
Differential reflectance spectroscopy (DRS) is a surface analytical technique. It uses ultraviolet (UV), visible, or infrared (IR) light as a probing medium. The interaction of light with “strongly absorbing materials”, such as metals, alloys, semiconductors, etc. occurs in the first 10–20 nm.
What is diffuse reflectance spectroscopy (DRS)?
UV–vis diffuse reflectance spectroscopy (DRS) is an especially useful technique to characterize the local titanium environment in titanosilicates . Figure 3 depicts the UV–vis DRS of calcined sample D.
What is the difference between diffuse reflectance and photoacoustic IR spectroscopy?
Diffuse reflectance and photoacoustic IR spectroscopy are techniques that can be employed when sample materials are opaque. Diffuse reflectance (DR) IR analysis can be used to obtain IR spectra of species separated by TLC without removing them from the TLC plate.
What is the UV-vis reflectance of Spectralon®?
White Standards Spectralon® thermoplastic resin, excellent reflectance in UV-vis region ¾KBr: IR (43500-400 cm-1) ¾BaSO 4: UV-vis ¾MgO: UV-vis ¾Spectralon: UV-vis-NIR © F.C. Jentoft FHI Berlin 2008 Specular Reflection: Angular Distribution
How to collect diffuse reflectance UV-Vis-NIR spectra in in situ SCR-NOx reaction?
The diffuse reflectance UV-Vis-NIR spectra were collected at in situ SCR-NOx reaction using through-flow optical cell at identical conditions as the catalytic test. The in situ FTIR spectra were monitored on a thin plate located, in a heated through-flow cell at approx. the same GHSV value.