Column: Molecular Spectroscopy Workbench

David Tuschel is a Raman applications manager at Horiba Scientific in Edison, New Jersey, where he works with Fran Adar. David is sharing authorship of the "Molecular Spectroscopy Workbench" column with Fran.

Articles

To better understand Raman spectral profiles, we briefly examine spectral line shapes, while discussing spectral shape, bandwidth, and broadening as percentage of Gaussian and Lorentzian components.

Peak Shape and Closely Spaced Peak Convolution in Raman Spectra

Fran Adar is the Worldwide Raman Applications manager for Horiba Jobin Yvon.

We illustrate how matching the optical properties of the microscope objective with the sample properties improves the spatial resolution and chemical speciation in depth profile measurements using confocal Raman microscopy.

Effect of Sampling Optics on Raman Depth Profiling

Raman and photoluminescence spectroscopy were combined with imaging to examine the spatial variation of solid-state structure and electronic character of two-dimensional (2-D) tungsten disulfide (WS2) crystals, which represent a family of new inorganic 2-D materials.

Combined Raman and Photoluminescence Imaging of Two-Dimensional WS2

Raman spectroscopy is extremely useful for characterizing crystalline materials.

Raman Crystallography and the Effect of Raman Polarizability Tensor Element Values

Low frequency Raman scattering measurements can be used to predict
physical properties of polymers and the crystalline polymorphic form of
active pharmaceutical ingredients (APIs). These measurements are made by recording the Stokes and anti-Stokes side of the laser line with the laser centered on the detector. Spectra of polyethylene and linear alkanes were recorded down to 4 cm-1.

Very Low Frequency Measurements of Linear Alkanes

Raman imaging provides detailed crystal orientation information for two-dimensional MoS2 prepared by chemical vapor deposition on silicon substrates. These two-dimensional crystals consist of individual atomic layers of sulfur, molybdenum, and sulfur atoms.

Effect of Layer Number and Crystal Stacking Orientation on the Raman Spectra of Two-Dimensional MoS2

Raman microscopy, combined with X-ray fluorescence, can provide detailed information about extractables and leachables from medically implantable devices.

Use of Raman Microscopy to Characterize Extractables and Leachables

Raman measurements can be used to infer the temperature of a material based on the Stokes and anti-Stokes band signal strengths, and by applying a predefined mathematical relationship. In reality, the temperature, Raman shift, and laser excitation wavelength all interact, and should be considered to better understand these measurements.

Raman Thermometry: Understanding the Mathematics to Better Design Raman Measurements

Raman 2D-COS spectral data provide information on conformational changes of polymers. Here, Raman spectra of ethylene vinyl acetate and vinyl acetate copolymer are measured and interpreted, enabling a description of morphological changes related to the vinyl acetate group.

Raman Analysis of Ethylene Vinyl Acetate Copolymers–Using 2D-COS for Identifying Structural Changes

When stress is applied to an object, it can produce strain. Strain can be detected through changes in peak position and bandwidth in Raman spectra. Here, we show examples of how strain in technologically important materials appears in
the Raman spectra.