Chemistry

IR and Raman spectroscopy

IR and Raman spectroscopy


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Spectrum smoothing (Smooth)

The smoothing of noisy spectra takes place with the help of spectra processing programs. The following animation explains the boxcar method.

The most commonly used method for spectrum smoothing is the Savitsky-Golay method. There is no averaging of the data points. The data set is adjusted with a polynomial function. The following applies: The higher the polynomial, the lower the smoothing.

Tab. 1
Advantages and disadvantages of smoothing
advantagesdisadvantage
More information from the spectra Improvement of the signal-to-noise ratio CosmeticsThe resolution is worsened. The half-value width becomes larger. Bands can disappear with improper smoothing (oversmooth)

IR and Raman Spectroscopy - Chemistry and Physics

Hagen-Poiseuille: In this experiment the flow rate through capillary tubes of a given diameter as a function of the height of the liquid column and the flow resistance as a function of the capillary radius are to be determined.

viscosity: The dynamic viscosity h of liquids is determined using the Haake falling ball viscometer.

Preparation:

H. Tritthart: Medical Physics and Biophysics, 2001, Schattauer GmbH Stuttgart

Cape. 2.2 Structure of Matter Liquids Chap. 2.3 Hydrostatics and hydrodynamics Hydrostatic pressure Hydrodynamics Flow direction and flow strength Laminar and turbulent flows, Reynolds number Hagen-Poiseuille law
Cape. 1.5.3 Frequently occurring distribution functions Normal distribution function Chap. 1.5.5 Regression line Chap. 1.6 Presentation of measured values.

W. Hellenthal: Physics for physicians and biologists, 7th edition 2002, Wissenschaftliche Verlagsgesellschaft mbH Stuttgart

Cape. 3.2 Liquids Section 3.2.1 Gravity pressure, stamp pressure Section. 3.2.4 Friction-free liquid movement Chap. 3.2.5 Viscosity (toughness, internal friction)

A. Trautwein, U. Kreibig, E. Oberhauser, J. Hüttermann: Physics for physicians, biologists, pharmacists, 5th edition 2000, Walter de Gruyter Berlin

Cape. 5.3 Macroscopic mechanical properties of liquids Chap. 5.3.2 Hydrostatics Chap. 5.3.2.2 Pressure in liquids 5.3.3 Hydrodynamics Chap. 5.3.3.1 The continuity equation Chap. 5.3.3.2 Viscous liquids Chap. 5.3.3.2.1 Viscosity chap. 5.3.3.2.2 Laminar flow 5.3.3.2.3 Turbulent flow Chap. 5.3.3.2.4 Laws of flow and blood circulation

Lecture notes physical basics of measurement technology, part 1, 3 and part 6.

Download: Representation of Hagen-Poiseuille

Application examples for the physical terms viscosity and flow resistance


IR and Raman Spectroscopy - Chemistry and Physics

and once again a problem that I am currently failing with. Here's the question:

----
The strongest frequencies in the Raman spectrum of HIO3 call the IO2 deformation oscillation (

320 cm-1), the I-OH stretching vibration (

650 cm-1) and the symmetrical / asymmetrical IO2 stretching oscillation (

800 cm-1). Which statements about the Raman spectrum of HIO3 are correct (multiple answers possible)?
A- The I-OH stretching vibration of HIO3 is also IR-active.
B- In the oscillations that are responsible for the bands at 650cm-1 and 8000cm-1, the O-I-O bond angles of the HIO3 molecule change.
C- The asymmetrical IO2 stretching is also IR active.
D- Vibrations that are active in Raman spectra are never IR-active.

Regarding A: According to the alternative ban, I understand it to mean that it cannot be IR-active.

Regarding B: I could well imagine. If the I-OH bond is stretched, it should have an impact on the O-I-O bond

Regarding C: Thought asymmetrical oscillations would be forbidden in Raman spectroscopy. So how can it & quota also & quot at IR-Sp. be active? If only at the Ir-Sp. or?

Regarding D: According to the alternative, is the prohibition correct?

As you can see, I really have some problems of understanding. Hope you can help me out!
----

And one more question regarding the topic:
Which statements about Raman spectroscopy are correct (multiple answers possible)?
A- The Raman effect is based on the absorption / emission of photons when matter is irradiated with electromagnetic radiation.
B- In Raman spectroscopy, a similar wavelength range of electromagnetic radiation is used as in infrared spectroscopy.
C- The structural information of a sample drawn from the Raman spectrum and the infrared spectrum of the sample are identical.
D- The Raman effect is based on inelastic scattering of photons when matter is irradiated with electromagnetic radiation.

Regarding A:
Correct, because the oscillation causes a change in the dipole moment. At the same time, it also changes the polarizability of the molecule and is therefore also Raman-active. (Note: The alternative prohibition only applies to a molecule with a center of symmetry ^^)

Regarding B: The molecule does not change the O-I-O bond angle during these oscillation processes.

Regarding D: No. See answers A and C.
----


Regarding A: No. The Raman effect is based on the inelastic scattering of photons when they hit matter.


Special partial information

Liquids and glasses
Raman spectroscopy on liquids and glasses - Format: PDF

Classification of pollen
Raman spectroscopy as a tool for the characterization and classification of pollen

Evaporation equilibria
In-situ Raman spectroscopy of evaporation equilibria: measurement of two-component systems under increased pressure and temperature. Dissertation, 2003. University of Bochum

Evaporation equilibria
In-situ Raman spectroscopy on evaporation equilibria. Measurement of two-component systems under increased pressure and temperature. Dissertation, (2003). University of Bochum - Format: PDF


Absorption of IR radiation

Interaction between electromagnetic radiation and the molecule can only occur if there is a moving electrical charge in the molecule. This is always the case when the molecule has either a changeable or an inducible dipole moment (IR-active). In molecules with vibrations symmetrical to the center of symmetry, there are no changes in the dipole moment (IR inactive).

Position of the IR absorption bands

Stronger chemical bonds and atoms of smaller mass cause absorption maxima in the IR spectrum at large wave numbers (high energy), whereas large masses cause IR absorption maxima at small wave numbers (low energy) (see deuteration). The energy is proportional to the square of the permanent dipole moment. Therefore, polar molecules provide intense rotational transitions. However, if one compares the amplitudes of the peaks of a single molecule with one another, it is noticeable that the strength of the transitions increases with each other J gain weight quickly at first, go through a maximum and finally for large ones J fall off again. The reason for this is that the strength reflects the degeneracies of the various rotational states and the occupation numbers of the rotational levels in the initial state. The degree of degeneration increases with increasing J to what leads to a higher energy. On the other hand, the occupation numbers decrease with increasing energy, which ultimately leads to a decrease in radiation intensity.

IR spectra are interpreted to mean that one tries to find out the molecular shape from the curve of the measured IR spectrum. The different vibration variants of the molecules are measured. A typical IR spectrum ranges from 4000 cm -1 to 400 cm -1 (wave number). The wave number is given in the somewhat unusual unit cm -1. One can, however, easily calculate the excitation energy from the wave number by using the wave number H and c (Planck's quantum of action and speed of light) multiplied. In an IR spectrum, each molecule leaves a typical pattern. From about 1500 cm -1 down, the causes for the spectrum can hardly be traced back to specific groups of molecules. This is the so-called fingerprint area. It cannot determine the structure of a molecule, but this area is a kind of “fingerprint” of the molecule.

Since in practice there are of course mostly no pure substances but mixtures, an exact composition can often not be derived from an IR spectrum. However, it is often enough to know which group of substances it is.

Vibration data of important groups of molecules

The following list contains examples of some molecular groups and the associated areas of the absorption bands:

  • C-H: 2850–3200 cm -1 (stretching vibration)
  • C-H: 1400 cm -1 (deformation vibration)
  • C = C: 1650 cm -1
  • C≡C: 2200-2500 cm -1
  • UH: 3200-3600 cm -1 very typical: smeared over a large width
  • OH: 2500-3000 cm -1 in carboxyls
  • C = O: 1700 cm -1
  • C≡N: 2260–2200 cm -1 stretching oscillation, e.g. in ABS or SAN (see picture)
  • NH: 3100-3500 cm -1
  • NO2: 1500 cm -1
  • C-X: -1 where X is a halogen
  • O = C = O: 2349 cm -1 carbon dioxide, appears in spectra as a result of the different path lengths of the two light beams (dispersive devices) or insufficient flushing with nitrogen (FT-IR devices)

Spectroscopy

to explore at all levels - from elementary particles to stars.

IPG lasers for spectroscopy offer:
& bull Wavelengths from UV to mid-infrared
& bull CW lasers, nano-, picosecond and femtosecond pulses
& bull Average performance in the MW to & gtkW range
& bull Fixed frequency or tunable light sources
& bull single frequency to broadband
& bull Outstanding beam position stability
& bull Outstanding beam position stability

Raman scattering is an inelastic light scattering method and enables one
nondestructive spectroscopic method in which the
& ldquo vibration fingerprint & ldquo of an analyte molecule after its photo excitation and
a subsequent change in its molecular polarization is measured. To
It was first discovered in 1928 because of its scientific nature
Versatility Achieved notoriety. Its areas of application include art,
Archeology, Life Sciences, Analytical Chemistry, Solid State Physics,
Fluids and interactions between fluids, nanomaterials,
Phases, drug studies and forensics. Raman spectroscopy
has found extensive use in various industries. For example
is used in the biopharmaceutical industry for the identification of
active pharmaceutical ingredients, in the semiconductor industry for the investigation of the
Purity of wafers and in forensics for monitoring the
Explosives detection used.

Lasers of different wavelengths can be used in Raman spectroscopy
to initiate the excitation process of the respective molecule. Of the
Most of these excited molecules scatters the light as elastic
Rayleigh scattering of the same energy. For a few, the
Vibration status during the relaxation, however, in the electronic
Ground state, whereby an energy shift of the scattered light occurs,
which is characterized by the energy in this vibration mode. That is
the Raman effect. IPG offers a wide range of CW lasers with
UV, visible and IR wavelengths for traditional Raman spectroscopy
as pulsed lasers like that CLPF in the mid-infrared range for
the state-of-the-art femtosecond-stimulated Raman spectroscopy. Such
Laser systems can, as in the case of surface-enhanced Raman spectroscopy
(Surface Enhanced Raman Spectroscopy, SERS) also for the excitation of plasmonic
Substrates are used.

Raman spectroscopy is used today in various industries and areas
extensively used, including semiconductors and superconductors, pharmaceuticals, medicine,
optical communication and scientific research.

In the context of laboratory research, the concept of pump-probe spectroscopy is used for examinations using conventional ultra-short-time laser spectroscopy. In the general case there are two separate ones optical femto- or picosecond pulses necessary:
one to excite (& ldquoPump & ldquo) the respective sample and another to test (& ldquoProbe & ldquo) the de-excitation of the sample. Both pulses must overlap spatially and temporally. An optical delay path can effectively lengthen the path of the sample pulse, thereby delaying it in relation to the pump pulse. When the pump pulse excites the molecule, the increasingly delayed sample pulse monitors the decay of the excited electrons. From this, dynamic, time-resolved data for the respective sample can be derived and analyzed. Pump-probe spectroscopy is mostly used to monitor the regeneration of saturable absorbers after photo-induced excitation in order to measure the time signatures of chemical reactions or the energy transfer between molecules. This information can
can then be used as a basis for the further development, representation and use of the investigated materials for a multitude of applications, for example for photocatalysis, photoelectrochemistry and photovoltaics. The major industries that pump-probe spectroscopy technology is used in are academia, aerospace, metallurgy, biophotonics, microscopy, and medicine. With the aid of such pump-probe methods, the efficiency of solar cell materials or the charge carrier recombination efficiency of water hydrolysis materials for the generation of residue-free burning hydrogen fuel can be determined by monitoring the decisive excitation and recombination dynamics.

Investigating the dynamics using pump-probe spectroscopy offers deeper and more fundamental insights into the properties of the material being investigated. As a dynamic measurement, it provides information that supplements that of stationary measurements. Based on these considerations, IPG pulsed fiber laser with wavelengths from 355 nm to 1.5 µm with femtosecond pulse widths (or picosecond pulse widths) and pulse energies, which enable comprehensive investigations with temporal resolutions in the femtosecond range in the above-mentioned applications.

Cavity Ring Down Spectroscopy (CRDS) is an optical method that can be used to measure the optical absorbance of materials that scatter and absorb light. The method has been widely used in the field of gas phase analysis and enables gas samples to be quantified in the ppt range (parts per billion). In one such experiment, a laser is used to illuminate an optical resonator. In resonance with the resonator mode, laser intensity builds up due to constructive interference. After switching off the laser, the exponentially decreasing light intensity is measured. Due to the sensitivity of the procedure, this application is particularly suitable for
Environmental monitoring, emissions monitoring and biopharmaceutical processes are useful. A prime example is the measurement of greenhouse gases, which has ensured the development of increasingly environmentally friendly technologies in a wide variety of areas - from automotive engines to chemical processing plants.

Since cavity ring-down spectroscopy is based on the absorption of light by gaseous substances and different gases absorb light at different wavelengths, varying laser wavelengths are required to successfully carry out such an experiment. IPG therefore offers a wide range of CW lasersthat can support the application requirements for gas absorption. Most typical gases have specific absorption spectra at wavelengths in the mid-infrared range, such as Hybrid laser
in the mid-infrared range of IPG
.


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Dairy Analyzers

Bruker offers high quality and high precision milk and milk analyzers for milk laboratories to standardize the routine milk production process.

FT-IR microscopes

Bruker Optics offers a wide range of FT-IR and Raman microscopy products.

FT-IR research spectrometer

Bruker Optics offers a wide variety of Ft-IR spectrometers in the laboratory for all of your research applications.

FT-IR routine spectrometer

Bruker Optics offers a wide variety of Ft-IR spectrometers in the laboratory for all of your routine and life science applications.

FT-IR / NIR for process control

Bruker FT-IR and FT-NIR spectrometers for reaction monitoring and process control in the pharmaceutical, food, agricultural and chemical sectors.

FT-NIR spectrometer

FT-NIR spectroscopy is now established for quality control applications in all industries, including the pharmaceutical, food, agricultural, and chemical industries.

Gas analysis

The MATRIX-MG series consists of three powerful FTIR gas analyzers in a compact and robust housing. They are designed for the automated, high-precision and real-time monitoring of gas concentrations in many different applications.

OPUS - spectroscopy software

OPUS is the leading spectroscopy software for the most modern measurement, processing and evaluation of IR / FTIR, NIR and Raman spectra.

ONET network software

The ONET software is a server application that is accessed via a browser-based web interface (WebUI) and with which a network of FT-IR or FT-NIR devices can be set up, managed and controlled from anywhere in the world.

Raman microscopes

Bruker offers high-resolution, high-performance Raman microscopes for analysis and research solutions.

Raman spectrometer

Bruker offers high-resolution, high-performance Raman spectrometers for analysis and research solutions.

Remote sensing

Bruker Optics offers a wide range of remote sensing scanning imaging FTIR spectrometers for the analysis of gases, liquids and solids.

Silicon analyzer

Silicon quality control for the photovoltaic and electronics industry. Highly sensitive silicon impurity analysis of carbon, oxygen, boron, phosphorus and more.

Terahertz

Terahertz spectroscopy for areas of application such as polymorphism, polymer research, inorganic chemistry, gas spectroscopy, solid-state and semiconductor physics, pharmaceutical or drug-related research. In particular, the combination of classic FT-IR and THz spectroscopy can provide a deep insight into the sample properties.


Applications of infrared and Raman spectroscopy in industry

Infrared and, to a lesser extent, Raman spectroscopy are well-established and really commonplace techniques in a well-equipped industrial laboratory. They are routinely used to address problems that are critical to the success of a research and development industry.

Investigation of catalyst structures and surface adsorption sites for catalysis can include isotope substitution and in situ determinations at medium to high pressures and temperatures. For in situ investigations of catalysts, Raman spectroscopy is the simpler method, since the carrier material has no influence.

Investigations at high pressures are important for model studies in oil production research, since band positions and intensities of gaseous / liquid mixtures of hydrocarbons are correlated with the pressure and used for the analysis of the composition.

Relatively new developments in vibrational spectroscopy, such as microscopic techniques and microscope arrangements, affect all areas of research and development that are typical of the oil industry. In Raman spectroscopy, this includes the spatial separation of sample and detection system, which is bridged by optical fibers, and many sample techniques in IR spectroscopy such as IRAS, DRIFT and FTIR-PAS. In situ IRAS is a very powerful method for investigating coated metal surfaces, adhesive layers and the behavior of coatings over time during heat treatment.

Many analytical problems involve complex mixtures which can be solved by combined processes such as GC / FT-IR or TGA / FT-IR. A mobile FT-IR spectrometer is also an interesting and very useful concept. Finally, examples of individual spectroscopic analyzes are shown that use either the special or the complementary possibilities of FT-IR and Raman spectroscopy.


Application Resources

With minimal sample preparation pharmaceutical customers can employ Raman in several stages of their workflow formulation and development or quality control. Raman can quickly identify chemical structure to pin-point defects / contaminants and maintain product consistency.

  • Rapid imaging for API distribution analysis
  • Non-destructive analysis for minimal sample preparation
  • Options for bulk sampling
  • Identification of isomers, hydrates and polymorphs
  • Verified reliability and stability of analysis

Webinar: Pharmaceutical Analysis with FTIR, Near-IR, Mid-IR and Raman in a Compact Platform

Desirable properties of consumer products are in a constant state of evolution requiring researchers and manufacturers to be three steps ahead. As such, polymer compound researchers are demanding tools that quickly identify failure modes, material distribution and material properties in complex compounds. Raman spectroscopy is capable of probing layered materials non-destructively, informing researchers on the structure and crystallinity of compounds, and offering spatial resolution below 1μm.

  • Visualization of 3D confocal spectral data
  • Quickly understand multi-layer samples at high resolution
  • Obtain data on structure and crystallinity

Researchers using multiple instruments or shared labs need to be experts in their application but can't be experts in analytical techniques. With the DXR3 Raman family of instruments, you can use Raman spectroscopy, microscopy, and imaging to advance your knowledge and reputation in your own field of work without mastering a new scientific technique. This family of instruments does not require an expert to set up the instrument, collect data or interpret the results.

  • Raman expertise is not required
  • Reliable performance drive by user-initiated internal automated alignment and calibration
  • Employed by shared labs for pharmacy, geology, materials science, life sciences, and chemistry

Raman analysis of semiconductor materials enable researchers and manufacturers to quickly analyze the behavior of new components and materials. The ability of Raman to detect stress in materials allows for quick and effective defect analysis - vital for electronics manufacturers trying to improve yield and reliability of products. The DXR3 Raman family offers a broad range of options to support the needs of electronics researchers and manufacturers from early-stage research to QA / QC.

  • Reliable performance driven by user-initiated internal automated alignment and calibration
  • Quickly understand thin film samples at high resolution
  • 2D and 3D correlation imaging to quickly visualize spectral data and inform customer decisions
  • Eliminate manual steps with automatic x-axis calibration

The complex nature of batteries requires a multi-faceted combination of electro chemical analyzes and materials characterization techniques. Raman spectroscopy has emerged as an important analytical technique that can be used for the characterizing for a variety of battery components. Battery researchers and developers need to understand the structural and material changes of battery components in order to optimize rate capability, distance on charge, discharge and safety.

  • Minimal sample preparation for ex situ analysis of anode and cathode material
  • Real time analysis of structural and material changes in lithium-ion batteries

Our use of plastics in everyday items and manufacturing processes has resulted in a deluge of slowly degradable materials entering our environment and our food chain. Academic and industrial researchers are leveraging new analytical techniques to identify and assess the risks of microplastics found in the environment and consumer products. Raman microscopy can help you identify, characterize, and quantify microplastics from a variety of sample sources (bottled water, ocean water, industry waste streams) without being a spectroscopy expert.


Formyl azide: properties and solid structure †

This work was funded by the DFG (WI 663 / 26-1, BA 903 / 12-3). We especially thank Prof. Dr. H. Willner (University of Wuppertal) for the generous support of this work and helpful discussions, as well as Prof. Dr. G. Rauhut (University of Stuttgart) for the calculation of anharmonic oscillation frequencies of HC (O) N3 at the CCSD (T) -F12a level.

Abstract

The simplest acyl azide, HC (O) N3, was produced as a pure substance and characterized with IR and Raman spectroscopy as well as the analysis of low-temperature single crystal X-ray diffraction (see solid-state structure C white, H gray, N blue, O red). The photolysis of the azide in CO-doped solid noble gas matrices provided the first experimental evidence for the elusive parent compound of acyl isocyanates, HC (O) NCO.

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ange_201209288_sm_miscellaneous_information.pdf562 KB miscellaneous_information

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Do not cite this version alone.

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IR and Raman Spectroscopy - Chemistry and Physics

Hagen-Poiseuille: In this experiment the flow rate through capillary tubes of a given diameter as a function of the height of the liquid column and the flow resistance as a function of the capillary radius are to be determined.

viscosity: The dynamic viscosity h of liquids is determined using the Haake falling ball viscometer.

Preparation:

H. Tritthart: Medical Physics and Biophysics, 2001, Schattauer GmbH Stuttgart

Cape. 2.2 Structure of Matter Liquids Chap. 2.3 Hydrostatics and hydrodynamics Hydrostatic pressure Hydrodynamics Flow direction and flow strength Laminar and turbulent flows, Reynolds number Hagen-Poiseuille law
Cape. 1.5.3 Frequently occurring distribution functions Normal distribution function Chap. 1.5.5 Regression line Chap. 1.6 Presentation of measured values.

W. Hellenthal: Physics for physicians and biologists, 7th edition 2002, Wissenschaftliche Verlagsgesellschaft mbH Stuttgart

Cape. 3.2 Liquids Section 3.2.1 Gravity pressure, stamp pressure Section. 3.2.4 Friction-free liquid movement Chap. 3.2.5 Viscosity (toughness, internal friction)

A. Trautwein, U. Kreibig, E. Oberhauser, J. Hüttermann: Physics for physicians, biologists, pharmacists, 5th edition 2000, Walter de Gruyter Berlin

Cape. 5.3 Macroscopic mechanical properties of liquids Chap. 5.3.2 Hydrostatics Chap. 5.3.2.2 Pressure in liquids 5.3.3 Hydrodynamics Chap. 5.3.3.1 The continuity equation Chap. 5.3.3.2 Viscous liquids Chap. 5.3.3.2.1 Viscosity chap. 5.3.3.2.2 Laminar flow 5.3.3.2.3 Turbulent flow Chap. 5.3.3.2.4 Laws of flow and blood circulation

Lecture notes physical basics of measurement technology, part 1, 3 and part 6.

Download: Representation of Hagen-Poiseuille

Application examples for the physical terms viscosity and flow resistance