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What is the difference ultraviolet and infrared spectroscopy?
FTIR spectroscopy cannot be used to detect all the vibration modes in a molecule. It can be used only to study the non-symmetrical vibrational state in an atom. Using Raman Spectroscopy one can study the symmetric stretch of the atom. For example the symmetric stretch of CO2 which cannot be studied by FTIR can be studied by Raman Spectroscopy. Here the permanent dipole moment of the molecule during a vibrational cycle does not change as it does not involve polarization. As a result, this mode cannot absorb infrared radiation. In many instances, vibrational modes that are not observed by infrared absorption can be studied by Raman spectroscopy as it is the result of inelastic collisions between photons and molecules
What are the Chemical processes or procedures used in forensic studies?
There is a vast amount of chemical processes involved in forensics, it all depends on what it is you rare testing and what you need to find out. Techniques include: * Gas chromatography - separates a compound into is constituents i.e. fire accelerants * High performance liquid chromatography - also separates compounds, can be used for drug analysis * Polarography - can test for the presence of heavy metals in liquids * Raman Spectroscopy - can be used for ink and paint analysis * Fourier Transform Infrared Spectroscopy - can be used for anything from drug analysis to paint analysis * Flame Absorption Atomic Spectroscopy - can be used to detect metal ions in mixtures
Name one advantages of raman spectroscopy?
a spectroscopic technique used to study vibrational, rotational, and other low-frequency modes in a system.[1] It relies on inelastic scattering, or Raman scattering, of monochromatic light, usually from a laser in the visible, near infrared, or near ultraviolet range. The laser light interacts with molecular vibrations, phonons or other excitations in the system, resulting in the energy of the laser photons being shifted up or down. The shift in energy gives information about the vibrational modes in the system. Infrared spectroscopy yields similar, but complementary, information.
Why can't absorption spectroscopy and x-ray diffraction be used to detect liquid elemental mercury?
Liquid mercury has not a spectrum of absorption in visible light; diffraction is not used for chemical analysis.
What is a Raman spectrometer used for?
A Raman spectrometer is a tool that is used for measuring low frequency modes such as vibrations or rotations. It is used mostly in chemistry although it is also used in physics to measure temperature.
What is the difference ultraviolet and infrared spectroscopy?
FTIR spectroscopy cannot be used to detect all the vibration modes in a molecule. It can be used only to study the non-symmetrical vibrational state in an atom. Using Raman Spectroscopy one can study the symmetric stretch of the atom. For example the symmetric stretch of CO2 which cannot be studied by FTIR can be studied by Raman Spectroscopy. Here the permanent dipole moment of the molecule during a vibrational cycle does not change as it does not involve polarization. As a result, this mode cannot absorb infrared radiation. In many instances, vibrational modes that are not observed by infrared absorption can be studied by Raman spectroscopy as it is the result of inelastic collisions between photons and molecules
What is stellar spectroscopy used for?
The purpose of stellar spectroscopy is to determine the chemical composition of stars, the temperature and some other characteristcs..
What are the Chemical processes or procedures used in forensic studies?
There is a vast amount of chemical processes involved in forensics, it all depends on what it is you rare testing and what you need to find out. Techniques include: * Gas chromatography - separates a compound into is constituents i.e. fire accelerants * High performance liquid chromatography - also separates compounds, can be used for drug analysis * Polarography - can test for the presence of heavy metals in liquids * Raman Spectroscopy - can be used for ink and paint analysis * Fourier Transform Infrared Spectroscopy - can be used for anything from drug analysis to paint analysis * Flame Absorption Atomic Spectroscopy - can be used to detect metal ions in mixtures
Why are metals Raman inactive?
Metals have the ability to shield external electric field, therefore when laser light used for excitation in Raman spectroscopy falls on the metal surface, it cannot penetrate very deeply. Also, noble metals have crystal structures with only one atom per unit cell, therefore only acoustic phonons exist, and no optic phonons that could be detected with Raman. Exceptioon is gallium - see ref. J.A. Creighton and R. Withnall Chemical Physics Letters , volume 326 (2000) pages 311-313.
How does IR spectroscopy works?
IR spectroscopy works by using infrared beams to work out the structure of a chemical. The chemical is placed in an inert substance, e.g. Potassium Bromide. The refraction of the beams brings up a characteristic trace of the mystery compound, which can then be used to work out the structure.
Did C.V Raman's discovery help people?
Raman spectroscopy is used in combustion diagnostics. Being a completely non-intrusive technique, it permits the detection of the major species and temperature distribution inside combustors and in flames without any perturbation of the (mainly fluid dynamic and reactive) processes examined. Cleaner running engines are possible.
Why Raman spectroscopy is prefered than other techniques?
Raman is used a lot as it is not sensitive to atmospheric water and CO2 usually won't stand out on the spectra. Its also useful in most settings as there is no sample prep needed, which is quite a difference to somthing like IR spectra which need nujol mulls or KBr plates. In comparison to IR the bands of the spectra are usually smaller and sampling is non-destructive. In an industrial setting raman can be used with fiber optic cables to remotely monitor reactions and product formation.
When is flame emission spectroscopy used?
It can be used for element identification and can used in Atomic spectroscopy and can be used to help "atoms with low ionization potentials become ionized."
Name one advantages of raman spectroscopy?
a spectroscopic technique used to study vibrational, rotational, and other low-frequency modes in a system.[1] It relies on inelastic scattering, or Raman scattering, of monochromatic light, usually from a laser in the visible, near infrared, or near ultraviolet range. The laser light interacts with molecular vibrations, phonons or other excitations in the system, resulting in the energy of the laser photons being shifted up or down. The shift in energy gives information about the vibrational modes in the system. Infrared spectroscopy yields similar, but complementary, information.
Advantages of Mass spectroscopy?
Mass spectroscopy is a highly sensitive technique that can accurately determine the molecular weight of a compound. It can provide information about the chemical structure and composition of a sample. Mass spectroscopy is also versatile and can be used in various fields like chemistry, biology, and environmental science.
Why can't absorption spectroscopy and x-ray diffraction be used to detect liquid elemental mercury?
Liquid mercury has not a spectrum of absorption in visible light; diffraction is not used for chemical analysis.
What is mass spectroscopy used for?
Mass spectroscopy can be used for a series of applications, ranging from the determination of chemical elements and chemical compounds in all kinds of samples to the investigation of reactions and interactions of DNA with other substances. As in mass spectroscopy you detect chemical substances based on the ratio between their masses and the charges (only ions can be detected), a wide range of information can be obtained usually with only very low amounts of the substance that you want to investigate.
