Spectroscopy

Spectroscopy is a branch of analysis devoted to identifying elements and compounds through the measurement of the absorption, scattering, or emission of electromagnetic radiation by atoms or molecules. It is widely used in physical and analytical chemistry, as well as in astronomy and remote sensing. Questions and answers here have to do with anything that has to do with Spectroscopy.

1,815 Questions
Chemistry
Spectroscopy
Quantum Mechanics

What is the basic principle of microwave spectroscopy?

atoms vibrate at particular frequencies, depending on their energy. If the energy of a particular atom has a vibration frequency in the microwave domain then you can know it's energy by measuring it's frequency by, Energy = plank's constant (times) frequency => E=h*f

In spectroscopy matter interacts with electromagnetic waves which are classified on the basis of their frequencies. e,g ultraviolet, infra red, x rays, radio waves and microwaves. Each category brings out specific changes in the molecule like in UV electronic transitions are observed and in IR vibrational changes are observed. These changes are observed when the energy requirement of the compound matches with the energy of the wave which can be calculated by the formula mentioned above.

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Science
Spectroscopy

Why do wet things often look dark?

All surfaces eventually acquire scratches which tend to scatter light instead of reflecting it evenly. This makes things look dull and whiter. Wetting things tends to nullify the effect of scratches, which makes things look glossier and darker.

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Spectroscopy
Math and Arithmetic
Physics

What does it mean for something to be quantized?

It means that it is assigned a numerical 'value', numbers need Units to impart Meaning.

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Electrical Engineering
Spectroscopy

Did Anybody know about deltapsi2 software using ellipsometry?

Deltapsi2 is a very hard program to use. I have used about every type of software out there and would recommend WVASE32 or CompleteEASE. Both of these are very easy to use and have models that you can build complicated anisotropic structures as well as semi-absorbing and absorbing materials.

I am using on a ellipsometer developed in the laboratory where I am working. I have written some basic software to perform analysis, but you explain that its exists a very powerful software named "CompleteEase"

I would like to know, if it is possible to get it but I doubt a little bit because it is developped by a private company WOOLLAM as I have seen on the net.

Could you give me some advise about this software.

Thanks a lot

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Organic Chemistry
Spectroscopy
Electrostatics

How is the dipole moment formed?

a positive charge and a negative charge separated by a distance

A dipole moment (µ) is the end of the vectorial sum of the electrical charges within a molecule or compound. e.a. CH4 is 100% symmetrical and have the same elements attached to it, so µ = 0. However, if you replace one -H with a -Cl then the vectorial sum is no longer zero since the charge is pointing towards the most electronegative element, in this case to -Cl. This creates a dipole moment.

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Electromagnetic Radiation
Spectroscopy

What is spatial aberration?

Spatial aberration is a term used in optics that means how blurry something is.

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Solid State Physics
Spectroscopy
Quantum Mechanics

What is Planck's quantum theory?

Max Planck assumed that the radiation energy is emitted in discrete packets called quanta rather than in a continuous way. The energy E of the quantum is related to the frequency ν by E = hν. The quantity h, now known as the Planck constant, is a universal constant with the approximate value of 6.626 X 10^-34 Js

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Spectroscopy

Why you use KBr disk in FTIR spectroscopy?

KBr disk doesnt absorb in the IR spectrum

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Organic Chemistry
Spectroscopy
Chemical Bonding

What is a dipole moment?

Dipole moment is the measure polarity of a polar covalent bond .

In language of physics it can be defined as the measure of strength of electric dipole. It is defined as the product magnitude of charge on the atoms and the distance between the two bonded atoms. Its common unit is debye and SI unit is coulomb metre.

The magnitude of dipole moment is equal to the product of either charge and the distance between the charges and its direction is from -q to +q.It is directed from the (-)ve charge to the (+)ve charge.In fact, it is the behavior of a dipole.


A separation of charge forming a positive and a negative end of a molecule ~APEX

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Electromagnetic Radiation
Spectroscopy
Biochemistry

What is Colorimeter?

Colorimetry is the measurement of the wavelength and the intensity of electromagnetic radiation in the visible region of the spectrum. Colorimetry can help find the concentration of substances, since the amount and colour of the light that is absorbed or transmitted depends on properties of the solution, including the concentration of particles in it. A colorimeter is an instrument that compares the amount of light getting through a solution with the amount that can get through a sample of pure solvent. A colorimeter contains a photocell is able to detect the amount of light which passes through the solution under investigation. The more light that hits the photocell, the higher the current it produces, hence showing the absorbance of light. A colorimeter takes 3 wideband readings along the visible spectrum to obtain a rough estimate of a color sample. Pigments absorb light at different wavelengths.

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Painting and Watercolors
Colors
Spectroscopy

What color is the opposite of blue?

Orange is the color that is opposite of blue on the color wheel. They are color complements. The opposite of red is green, and the opposite of yellow is purple.

(By paired RGB colors, the secondary color complementary to blue is yellow, to red is cyan, and to green is magenta. Blue is also the same distance from the midrange of the visible spectrum as yellow.)

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Spectroscopy
Radio

What is ML band for a radio?

"Extremely High Frequency" (EHF) is the highest radio frequency band. It runs from 30 to 300 gigahertz and has a wavelength of ten to one millimeter, giving it the nickname millimeterwave or millimeter Band (mmW/ML Band).

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Chemistry
Spectroscopy
Comparisons

What is the definition of concentrated solutions?

Concentrated solution is a solution that contains a large amount of solute relative to the amount that could dissolve.

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Chemistry
Organic Chemistry
Spectroscopy
Chemical Bonding

How can you tell if there is a dipole moment or not?

A dipole moment is defined as a measure of the molecular polarity of a compound; the magnitude of the partial charges on the ends of a molecule times the distance between them (in meters). In order for there to be a dipole moment the element must must have molecular polarity which results from molecules with a net imbalance of charge (often a result of differences in electronegativity). If the molecule has more than two atoms, both shape and bond polarity determines the molecular polarity. In general look for a difference in electronegativity of the elements of a molecule which results in polarity and thus a possible dipole moment. Note that molecular shape influence polarity so molecules with the same elements but a different shape (and vice versa) won't have the same dipole moment.

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Chemistry
Spectroscopy

What examples of everyday objects with vivid emission spectra?

glass is an example of one

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Physics
Chemistry
Spectroscopy

Would two blocks made of the same metal but differ in sizes differ in density?

Density is dependent on two things - the volume of the object under consideration, and it's mass. For a given material, in order for the volume (the size) to change, so must the mass by a proportional amount. Therefore, for a specific material, changing the size of the sample does not affect the density in any way.

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Physics
Electromagnetic Radiation
Spectroscopy
Astrophysics

What is the wavelength of cosmic rays?

check the link under 'edit links' in the left column for details.

It is 10-16 m.

676869
Spectroscopy

What is the standard value of dispersive power of glass prism?

.04 to .05 typically about 0.47

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Science
Electromagnetic Radiation
Spectroscopy
Visible Light Spectrum

What is the electromagnetic spectrum?

The electromagnetic (EM) spectrum is the entire range of frequencies that electromagnetic radiation can have. The EM spectrum is divided into sections based on the common characteristics that certain frequency ranges have. These sections are, in order from low to high frequency, radio waves, microwaves, infrared waves, visible light (which from low to high frequency is further divided into red, orange, yellow, green, blue, indigo, and violet), ultraviolet waves, X-rays, and gamma rays. You can think of the EM spectrum as an invisible rainbow with visible light being a small part of it. And, like a rainbow, the edges of the divided sections are blurry; i.e. there is no exact frequency where one can say, for example, that this wave is no longer an X-ray, but is instead a gamma ray.

it is waves of light in order of their wavelengths and frequencies

APEX: A chart of frequencies of light waves.

525354
Technology
Solid State Physics
Spectroscopy
Optics

What is meant by Fresnel distance in optics ie diffraction how is it related to validity of ray optics please do make it simple as i am a beginner?

An aperature OS size a illluminated by a parallel beam sends diffracted light into a angle of approximately ~y/a. This is the angular size of the bright central maximum. In trevelling a distance z, the diffracted beam therefore acquires a width zy/a due to diffraction. this gives distance beyond which divergence of the beam of width a becomes significant. Therefore, z ~ a2/y we define a quantity ZF called the Fresenls distance by the following equation ZF= a2/y

For distance greater than ZF the spreading due to diffraction over that due to ray optics. The above equation shows that ray optics is valid in the limit of wavelength tending to zero.

596061
Spectroscopy
Visible Light Spectrum

What color has a wavelength of 410 nm?

It's purple

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Electromagnetic Radiation
Spectroscopy

How is a rainbow a physical change?

Ordinary yellow sunlight becomes a rainbow when different frequencies of light are bent in slightly different directions.

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Science Experiments
Spectroscopy

Uses of diffraction grating?

Diffraction gratings have many uses. Some of their uses include: spectrometers (devices which measure properties of light), monochromators (devices which only transmit rather narrow ranges of wavelengths of EM radiation chosen from sources which provide a greater range of wavelengths), but also fibre optic communication (wavelength division multiplexing, to be more specific, which allows different wavelengths of light to carry different signals over a single strand of the optical fibre), lasers and many more other things

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Computers
Electromagnetic Radiation
Spectroscopy
Visible Light Spectrum

What is electromagnetic spectrum?

A chart of frequencies of light waves. a.

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Electromagnetic Radiation
Spectroscopy

Is there a light stronger than Gamma?

The highest energy photons are described as Gamma. But in terms of the strength, there are more light sources that we encounter everyday of a greater intensity than gamma, as intensity is a measure of the number of photons arriving over an area in a given time. Therefore, visible light and infra-red from the sun are much more intense than the gamma we encounter everyday, as gamma photons are few and far between.

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