Spectroscopy is the study of the interactions between matter and radiated energy. Experimentally, the results are returned as a function of wavelength versus amplitude (intensity), where the spectral lines represent the resonance frequency of the sample.

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UV-VIS spectra of n-decanes

I was wondering if anyone knows where I can find UV-VIS spectra of the n-decanes. Specifically tetradecane and dodecane. I can't seem to find such information using my regular search methods, so I ...
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30 views

Photoelectric Effect in Semiconductors

Is the photoelectric effect possible for semiconductors? I imagine that this might be, if possible, a two-photon process: excitation of an electron from a filled to conductance band, and then on to ...
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Difference between torsion, out of plane, coplanar and perpendicular bends?

In Infrared spectroscopy, stretches are easily understandable. But, how do I visualize (or conceptually understand) the difference between dihedral (torsions), out of plane bends, coplanar bends, and ...
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Atmopsheric Gas IR-Spectra

I am looking for normal resolution IR-spectra of: $\ce{O2}$ and $\ce{N2}$ at high concentrations and; common minor gas in atmosphere: $\ce{H2O}$, $\ce{CO}$, and $\ce{CO2}$ at environmental ...
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light Intensity and its effects on energy and emitted electron on metal surface

we have a metal surface with electrons in a specific energy state say X ,now we shine light on it of specific wavelength and intensity. now what if i double the intensity of light , what would happen ...
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Help with identifying an unknown substance?

I have the following IR and NMR of an unknown substance. Can someone tell me what is a possible structure of the compound or point me in the correct direction. So far I am thinking of a benzene ring ...
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169 views

Identifying an unknown compound(w/ NMR/IR)?

I need some help identifying the following unknown compound. Any suggestions or hints regarding the possible compound would be highly appreciated. So far I am thinking the broad peak on the IR is an ...
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81 views

Interpreting the Infrared Spectroscopy(IR)?

I have already attempted to interpret some of the peaks. Please tell me if they are correct/incorrect and anything that I have missed. Thanks !
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36 views

Information depth in x-ray photoelectron spectroscopy (XPS)

What is 'information depth' in XPS and what does determine it? Also how does it depend on the 'take-off angle'?
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How can I determine/quantify the presence of boron nitride on a metal surface?

We use micron-grade hexagonal boron nitride (hBN) to coat the surface of bullets that are jacketed in gilding metal. This coating is mechanically embedded/plated onto the surface in order to increase ...
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Synthesizing monodisperse PbS quantum dots

For a research project, I am trying to synthesize lead (II) sulfide quantum dots using the method of Li et al.. Basically, I am injecting sulfur dissolved in 1-octadecene into a mixture of PbO, oleic ...
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121 views

How to make approximation of rotational partition function of diatomic linear molecules?

Using the rigid rotor approximation to the level energies, and such other appropriate assumptions, we can approximate rotational partition function, $Q_{\mathrm{rot}}$, of linear molecules as follows: ...
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Interpretation of the following IR?

I have the following IR Spectrum that I am trying to interpret: So far I am thinking this compound have: a primary amine due to two peaks at 3624 and 3533. The sharp peak 3416 could indicate an ...
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100 views

$\ce{^13}$C NMR of dimethyl 3,4,5,6-tetraphenylphthalate?

I am trying to assign the peaks here to dimethylphenylphatalate but all the benzene rings are throwing me off. All I can get is that the further most signal is the carbonyl carbon (168.71) and the ...
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49 views

Benzaldehyde NMR Question?

Assuming this image is correct, why is the Carbon-3 more deshielded than Carbon-2 and Carbon-1 ? From what I understand, deshielding is the greatest when the Carbon atom is closer to electron ...
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73 views

NMR Spectroscopy Question

From my understanding NMR spectroscopy works by analyzing the resonance frequency of each structure around a hydrogen or carbon. Since every structure is unique and has unique resonance frequency it ...
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21 views

What are some incapabilities that the early spectroscopy have when compared to the more modern method?

What are some incapabilities that the earlier spectroscopy (Visible, Ultraviolet and Infra-red) have when compared to the more modern method?
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HNMR - Peak Splitting

If you have $\ce{CH3-\color{\red}{CH2}-CH2Br}$ Then the $\ce{CH2}$ (in red) would have a peak splitting of $12$ because $(n+1)(m+1)$ where $n$ for the $\ce{CH3}$ is $(3+1=4)$ and m for $\ce{CH2}$ is ...
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Is visible spectroscopy the only non-electronic method of all the spectroscopy method?

Is visible spectroscopy the only non-electronic method of all the spectroscopy method? I know some of the spectroscopy method is possible being used because of electronics.
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How could a scientist from the 1800s to the 1920s run spectroscopy of chemicals?

How would such a scientist be able to get the spectroscopy of chemicals? Without access to modern computing or electronics how would it be possible? Any video link or reference link are much ...
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42 views

How to calculate the rotational constants for different states from a stick spectrum?

Given a stick spectrum for an unknown diatomic molecule, how do you determine the rotational constants $B_\nu$ for both the excited and ground states given that $$E_{j}=B_{\nu}j(j+1)$$
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122 views

Distinguish between symmetric and asymmetric molecules with IR

I get increasingly nervous as I get my organic lab course reports. For, I often get asked whether the peak in the IR comes from an asymmetric or symmetric stretch. I've looked at about ten books and ...
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895 views

Why is a singlet state called singlet and a triplet state called triplet?

I kind of get the idea of singlet and triplet states. But why are they called singlet and triplet (what is the single and what is the triple in these cases)? I feel that I am missing something ...
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What is the process involved in performing a mass spectrometry experiment?

I have heard that mass spectrometry is very time consuming: why is this? What is the process involved in performing a mass spectrometry experiment? What steps are the most time consuming?
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Could someone please explain the difference between m/z and m/e in mass spectroscopy

The definition: The abbreviation m/z is used to denote the dimensionless quantity formed by dividing the mass number of an ion by its charge number. It has long been called the mass-to-charge ratio ...
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72 views

Difference between an absorbance, emission, and excitation spectrum for uv-visible spectroscopy

The exam paper answer is 500, because we need the wavelength of "maximum absorbance." But this graph shows two curves, and the absorbance curve is omitted. But what is the difference between an ...
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111 views

How to calculate m/e value for the base peak in mass spectroscopy?

My working out: Propan-1-ol : CH3CH2CH2OH This can be broken up into: CH3 + CH2CH2OH CH3CH2 + CH2OH CH3CH2CH2 + OH Base peak = most abundant fragment formed (highest peak) How do i know which ...
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163 views

UV-Visible Spectroscopy in the analysis of sodium chloride in potato chips

Here is the question and answer out of an exam paper: Firstly, I thought UV-Visible can also use radiation in the visible spectrum. Also when analyzing sodium chloride (a molecule), then UV-Visible ...
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61 views

1H-NMR and deducing structures

here is the data booklet we must refer too: Here is the exam paper solution: I dont understand how they conclude this. Peak areas and the chemical shifts seem to be different for me. For ...
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28 views

Fluorescence Spectra, emission spectrum

What exactly does the excitation spectrum tell us about a sample in Florescence Spectroscopy, what information does it tell us? I know that we will get an output of concentration vs intensity but ...
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34 views

If absorbance is 0, what is the equilibrium constant?

If the absorbance of something is 0, what is the equilibrium constant? In a reaction, the absorbance is 0, so the concentration of the product is 0. The concentration of one of the reactants is also ...
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182 views

Why is filter paper fluorescent?

Typical filter paper used in chemistry lab (e.g. Whatman #1) exhibits autofluorescence in near UV with excitation maximum at 365 nm and emission maximum at 440 nm. It was reported in literature1 that ...
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55 views

Alcohol irregularities in Hydrogen NMR

We've started learning about NMR in my ochem class and my instructor told us that in Hydrogen NMR an alcohol can have a fairly wide range of possible values - usually from about 2 to 5. He said that ...
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64 views

Help with understanding term symbols

I think that I understand most of the parts of the symbol shown for ground state oxygen However, I was hoping that someone could tell me what exactly the negative superscript sign means? And how do ...
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95 views

Looking for raw interferogram data / raw FID data from FT-IR / FT-NIR / FT-NMR

I'm trying to get my hands on some raw interferogram data / raw FID data from an FT-IR / FT-NIR / FT-NMR so I can run some tests using FFT with it (it needs to be real data). Here's a picture below of ...
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How to get defect-energy level diagram from PL data

I am reading this article Phys. Chem. Chem. Phys. , 2011, 13, 14902-14905 and seen that the authors have drawn a image of defect level using PL data Can you explain me how this diagram can be drawn ...
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100 views

Does my data show quadratic regression in a calibration curve?

This data was taken for my science fair project, and I would like to know the relationship between spectrophotometer absorbance and cell density (taken manually) of algae after a toxicity test. The ...
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101 views

What is the approximate lifetime of an $S_N2$ transition state complex?

Imagine some $S_N2$ reaction involving an aliphatic $sp^3$ carbon with a halide leaving group (e.g. Iodide or Bromide). Given the rise of femtosecond spectroscopy (e.g. using a mode-locked ...
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192 views

Why does the excitation and emission spectrum of a fluorescent molecule have overlap?

Question is rather self-explanatory. Came up during a lecture without a concrete answer. I understand that the differences in emission wavelengths is due to relaxation to the lowest energy level of ...
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36 views

Red glow in the dark pigments

I want to do some spectrometry experiments with glow in the dark paints. The red paints I've read product details for all seem to require a uv light to charge. Are there any red glow in the dark ...
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50 views

Are there any molecules with the same spectrum?

Are there any two distinct types of atom or molecule that have identical emission or absorption spectra?
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69 views

Changes in defects in a material due to heat treatment

Currently i am doing some research on optical properties of a oxide material and for that purpose i have done some photoluminescence study on it. Because this is an ongoing research i cant divulge ...
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Understanding moseley's law from the rydberg-type equation?

To explain the characteristic X-ray emission peaks for various elemental targets, a formula was developed which was similar in construct to the rydberg equation for H-atom as derived by the ...
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167 views

How to use IR spectroscopy to determine structure of molecule

A molecule $\ce{XY2}$ is known to be linear, but it is not clear whether it is Y-X-Y or X-Y-Y. How would you use IR spectroscopy to determine its structure?
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How are non-Stoichiometric compounds determined?

For solids where the compound contains defects, the stoichiometric equation deviates from the "pure" one. How are these compounds determined? I am looking in my chemistry book but I do not see ...
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563 views

Effect of dopant size on XRD peak shift

If we add an impurity atom (doping) to the crystalline struture of another material and take the XRD of the doped material what kind of peak shift can we expect. For the better description of my ...
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3k views

What is the principle of diffuse reflectance spectroscopy behind band gap measurement?

As the title suggest can you explain how DRS can be used for finding band gap of a material. Below is an DRS output result: From the figure we can see that at about 465 nm the reflectance drops ...
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302 views

Which are the differences between resonance Raman and fluorescence?

If the fluorescence is the re-emitting of a photon with a larger wavelenght due to the transition from a higher energy state to a lower energy state the case of resonance Raman (where there aren't any ...
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Colors of soap, Dodecanol, and chlorosulfonic acid

I was wondering if anyone had any insight as to why the reaction of chlorosulfonic acid (colorless) and 1-dodecanol (colorless) produces a deep dark red colored solution? The reaction should give ...