What are the factors affecting the absorption properties of a chromophore in absorption spectroscopy?
916533
concentration of the chromophore and wavelength of light that it absorbs. the different wavelengths give the solution (chromophore) different colours.
1154066
It is not due to the chemistry of copper or gold.\n\nIt is due to the electronic band structure. The two metals unusually have a band structure that causes them to absorb light at certain frequencies rather than reflecting it.
545100
As no one else has had a crack at this, I'll have a go with my best guess. Have you access to a reflectance spectrophotometer? Instead of shining light through a sample, it measures light reflected from a sample. At a pinch, you might be able to modify a uv/vis spectrophotometer to measure this.\n\nI hope this helps.
978327
When a ligand binds to Cu, it splits the 5 d orbitals into two groups (off the top of my head I cant remember the names but I think they are t2g and eg).  The color results from electrons transitioning between the two d orbital levels.  Different ligands split the orbitals different amounts so you get different wavelengths of light emitted.  \nAlso, since it is technically forbidden to have an electron transfer within an orbital level, the d-d transition peaks are much smaller than other electron transitions.
507988
Since your question refers to only the types of detectors used in HPLC, I assume that you understand how HPLC works so I will not go into that.  Each chemical refracts light differently.  As the various components elute from the column, a beam of light is passed through the eluted flow.  The components come out as bands of individual components.  Each band or component refracts the light and this refraction is measured by a detector.  The signal from the detector is amplified and sent to a recording device which records the refractive index of that component.  From the refractive Index, the component can be identified and by the strength of the signal, the amount can be determined.  \n\nThe UV/Visible detector simply uses the different wavelengths of light to determine the various components being eluted.  Each component absorbs light rays differently.  The wavelength Can be varied depending on the class of compounds being examined.  This allows for maximum sensitivity of the detector.  As each component is eluted, it passes through the detector.  The absorbence of light gives the identification of the component and the amount of light absorbed is directly related to its concentration.
699805
It is caused by electrons being emitted...(aka photons aka light) but certain metals give off certain colours according to their wavelenght...and according to the line spectrum....
890060
This solution probably has fluorescence at UV (ultra violet) wave length. try looking at it in a room with red light, if there is no light using the lenses then it's confirmed. but you can't simply identify it this way. you have to know the exact wave length that it has fluorescence at. even then you might not be able to identify it. try using UV-visible spectroscopy and when you have its spectra, you can identify it. for more information see: principles of instrumental analysis by Skoog
952788
A=E*d*C\n\n(d=length of the path of the light through the solution)\n\nIf you have only one value of absorbance then obviously there is no way of determining the concentration without the molar extiction coefficient (E).\n\nIn practice even if you know E, you don't use it to find the unknown concentration. Instead you measure the A of standard solutions and do a standard curve. From the equation of that curve (which you find using linear regression) and the value of A of your sample you calculate the unknown amount. \nThe standard curve doesn't need to be A vs mole/lt. It can be A vs anything e.g. g/ml, mg/ml, ppm or even just g, mole, etc. the only thing that changes is what the slope represents.\nFor example for A vs mole/lt the slope corresponds to E*d, for A vs g/lt the slope corresponds to E*d/MW, etc.\n\nIf you  always have the same volume of sample you can do the curve A vs grams directly. Then if V is the volume of the sample, the slope corresponds to E*d*V/MW\n\nEven if your standard curve is expressed in moles/lt you can convert it to grams. You just need the MW of the compound and the volume, not E...
275302
"Normal" color pigments reflect (more precisely, they don't absorb) light having wavelengths corresponding to the perceived color of the pigment, and they absorb light with other frequencies.  The energy associated with the absorbed light goes ends up heating the material (i.e., into exciting atomic and molecular vibrations in the compounds in the pigment).  That energy is ultimately removed by thermal conduction (exciting atomic/molecular vibrations in material adjacent to the material doing the absorption), or re-radiated as low-frequency (e.g., infrared) electromagnetic radiation that we cannot see.\n\nFluorescent pigments differ in that some of the light energy that is absorbed gets re-radiated at wavelengths we can see.  In effect, fluorescent compounds convert incoming light of one wavelength into (visible) light of another wavelength, so the material seems to "glow" with a color corresponding to the wavelengths being emitted.  Normally, the re-emitted light has a longer wavelength (lower photon energy) than that of the absorbed light.  (It is possible for fluorescent emission to occur at a shorter wavelength than that of the absorbed light, but conservation of energy requires that the energy of the absorbed photon be "supplemented" with energy from some other source, such as the vibrational energy of the material or by absorption of multiple photons and emission of a single photon.)\n\nA detailed description of the physics involved can be found at <http://micro.magnet.fsu.edu/primer/techniques/fluorescence/fluorescenceintro.html>\n\nThere are numerous fluorescent compounds, each with distinctive absorption and emission characteristics <http://en.wikipedia.org/wiki/Category:Fluorescent_dyes>.   .  As an example, see the spectra of rhodamine B (a very important fluoroscent dye) at <http://omlc.ogi.edu/spectra/PhotochemCAD/html/rhodamineB.htmlz>.
259378
The principle of compounds having color can be traced with the number of conjugated double bonds of the compound. Dibenzalacetone contains many alternating double bonds which makes it colored. When light excites the double bonds, the electrons goes up from low electronic energy level to a higher level. The increase in conjugation makes it easier for electrons to jump to a higher energy level hence longer wavelength of light to be absorbed and transmitted
957910
The visible light region is from 0.7 µm to 0.4µm of the spectrum. The color of an object that we see is the color or wavelength of light reflected from the visible spectrum. All other colors or wavelength are absorbed. the following chemicals are different in terms of wavelength because of their different nature's regarding reflection of particular wavelength or the absorption of other.
971140
It is because of the conjugate dienes. i.e. Double bond C single bond C double bonds. C=C-C=C etc. These conjugated dienes absorb light in the visible spectrum and in this case it happens to be pale yellow.
710202
You are right! Atomic structure has everything to do with what wavelengths are absorbed, and which ones are reflected. I works with light, and it works with radio waves... Thats how they make stealth aircraft. Funny thing about copper... when powdered and burned, it makes a pretty green color!
220155
Are you asking for an explnation for the spectral proprties  or doy ou want the actual spectral report? either way go here....http://orgchem.colorado.edu/hndbksupport/irtutor/estersir.html
848206
The intensity of the absorption is proportional to the change in the bond dipole as the bond is stretched. A C-F bond has the greatest bond dipole on the list, so it will give the most intense absorption. A C-I bond is not very polar so we expect it to have the weakest absorption. The order is C-F > C-Cl > C-Br > C-I.\n\nEnergy: Stronger bonds are harder to stretch, but the energy is also dependent on the reduced mass of the atoms involved. Thus, it is not always trivial to make this prediction. Actual observed values are: C-F: 1400 - 1000 cm-1, C-Cl: 830 - 600 cm-1 (or below), C-Br: < 700 cm-1 and C-I: < 600 cm-1.\n\nIf you ever use IR instrument you will see that KBr is preferred over NaCL plates since KBr cut off is around 550 cm-1 where as that of NaCl i around 650 cm-1.
414639
Click on the source link.  The site contains the absorption as well as fluorescence spectra.
306417
Circular dichroism (CD), is the differential absorption of left- and right-handed circularly polarized light. It is a form of spectroscopy used to determine the optical isomerism and secondary structure of molecules.\n\nAt a given wavelength,\n\nΔA = (AL − AR) \nwhere ΔA is the difference between absorbance of left circularly polarized (LCP) and right circularly polarized (RCP) light (this is what is usually measured). It can also be expressed as:\n\nΔA = (εL − εR) C l \nwhere εL and εR are the molar extinction coefficients for RCP and LCP light, where C is the molar concentration and l is path length.\n\nThen\n\nΔε = (εL − εR) \nis the molar circular dichroism. This is what is usually meant by the circular dichroism of the substance.\n\nAlthough ΔA is usually measured, for historical reasons most measurements are reported in degrees of ellipticity.\n\nThe molar ellipticity is:\n\n[θ] = 3298Δε. \nIn general, this phenomenon will be exhibited in absorption bands of any optically active molecule. As a consequence, circular dichroism is exhibited by biological molecules, because of the dextrorotary (e.g. some sugars) and levorotary (e.g. some amino acids) molecules they contain. Noteworthy as well is that secondary structure will also impart a distinct CD to their respective molecules. Therefore, the alpha helix of proteins and the double helix of nucleic acids have CD spectral signatures representative of their structures.\n\nCD is closely related to the optical rotary dispersion (ORD) technique, and is generally considered to be more advanced. CD is measured in or near the absorption bands of the molecule of interest, while ORD can be measured far from these bands. In principle these two spectral measurements can be interconverted through an integral transform, if all the absorptions are included in the measurements.\n\nThe ultraviolet CD spectrum of proteins can predict important characteristics of their secondary structure. CD spectra can be readily used to estimate the fraction of a molecule that is in the alpha-helix conformation, the beta-sheet conformation, the beta-turn conformation, or some other (random) conformation. These fractional assignments place important constraints on the possible secondary conformations that the protein can be in. CD cannot, in general, say where the alpha helices that are detected are located within the molecule or even completely predict how many there are. Despite this, CD is a valuable tool, especially for showing changes in conformation. It can, for instance, be used to study how the secondary structure of a molecule changes as a function of temperature or of the concentration of denaturing agents. In this way it can reveal important thermodynamic information about the molecule that cannot otherwise be easily obtained. Anyone attempting to study a protein will find CD a valuable tool for verifying that the protein is in its native conformation before undertaking extensive and/or expensive experiments with it. Also, there are a number of other uses for CD spectroscopy in protein chemistry not related to alpha-helix fraction estimation. s\n\nCD spectroscopy is usually used to study proteins in solution, and thus it complements methods that study the solid state. This is also a limitation, in that many proteins are embedded in membranes in their native state, and solutions containing membrane structures are often strongly scattering. CD is sometimes measured in thin films.\nCD has also been studied in carbohydrates, but with limited success due to the experimental difficulties associated with measurement of CD spectra in the vacuum ultraviolet (VUV) region of the spectrum (100-200 nm), where the corresponding CD bands of unsubstituted carbohydrates lie. Substituted carbohydrates with bands above the VUV region have been successfully measured.\n\nMeasurement of CD is also complicated by the fact that typical aqueous buffer systems often absorb in the range where structur