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Questions tagged [optical-properties]

Questions related to color as well as the reflecting and refracting properties of chemicals.

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Why all commercial SPR instruments use angular interrogation?

Surface plasmonic resonance biosensor devices are used to measure analyte concentration, kinetics, affinity, and specificity without any need for labels. This technique involves the bonding of the ...
C.X.F.'s user avatar
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What compound has the strongest optical rotation of polarised light?

A question recently asked here whether compounds know to be chiral can have non-measurable optical rotations: Are there chiral compounds that don't rotate plane-polarized light?. Apparently they ...
matt_black's user avatar
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Is there any molecule describable by three-level with mixed parity and transition dipole moments in different directions?

I would like to know if there are molecules described by a three-level system with mixed parity and transition dipole moments in different directions. By mixed parity I mean all three transitions can ...
Pu Zhang's user avatar
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How to align povidone-iodine molecules in order to look for optical polarization

In this answer I mention how early polarizing filters (e.g. sunglasses) were made by doping a polymer with iodine atoms and then stretching the film to orient the polymer molecules. Electrons donated ...
uhoh's user avatar
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Is optical activity of a given compound a statistical picture?

When optical activity is taught it is done in terms of single molecules. But when it is actually measured it is done on a large collection of such molecules. So, how does the asymmetry manifest itself ...
Swaroop Chandra's user avatar
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Detection of contamination from salicylic acid via either single excitation fluorometer or via absorbance

My colleague detected fluorescent contamination likely from salicylic acid in some water samples. I have made a new batch and want to check whether my new samples also have this contamination. 1. Can ...
claire's user avatar
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Does optical isomerism fall under the category of stereoisomerism?

I have been asked to find the total number of dichlorination products (including stereoisomers) for the following reaction: I have figured out nine possible structures out of which two are optically ...
Aniruddha's user avatar
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3 votes
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A formula for the refractive index of a gas dependent on temperature and pressure

I am in search for a formula that gives me the refractive index of a gas at a given temperature and pressure. Does such a formula exist? Ideally the solution should have this form: $n_g(t, p) = \...
Jhonny007's user avatar
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Why upon melting of PEO between crossed polars colours appear?

Crystalline PEO when under crossed polars shows distinct Maltese cross pattern. Being birefringent, when polymer crystal align with the polarizer or analyser it shows extinction regions (effect known ...
Wojtek Adamczyk's user avatar
1 vote
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DIY hydrolysis of starch with copper and test them with polarizer sheet due to muta rotation

When I read about muta rotation — the interconversion of alpha to beta glucose — recently, I decided to do it with rice, because rice contain 66% of starch which is alpha glucose polymer. To hydrolyze ...
karthik keyan smk's user avatar
1 vote
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What is the diffusivity of colloidal Formazine in water?

I have synthesized Foramzine in an aqueous solution (turbidity = 4000 NTU), and will be further diluting it. I would like to know the diffusion coefficient (diffusivity/mass diffusivity) of colloidal ...
optomechanic's user avatar
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Is there a stretchable, transparent polymer like PDMS, but not so hydrophobic?

I'm looking for something like PDMS, but not as hydrophobic. I'm trying to form 2d crystals using the surface tension of an evaporating droplet to organize microspheres into an ordered array. PDMS ...
Thomas's user avatar
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Beer-Lambert law absorption by each species

Light travels length $l$ through a medium with $n$ independently absorbing species with extinction coefficients $\alpha_1,\dots,\alpha_n$. According to Beer-Lambert law, the amount of light absorbed ...
arax's user avatar
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Calculating Optical Absorption Spectra using Ab Initio Computations

My main question is, How does one compute the optical absorption spectra of a molecule by using say, Configuration Interaction energy and associated transition dipole moments. I am trying to use an ...
R. Basuhi's user avatar
1 vote
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What home chemical can I use to make droplet lens?

I'm very interested in making homemade droplet lens, I want to know what home element can I use to cook them. Here's a video showing the process, with no further information:
user1532587's user avatar
1 vote
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Liquid crystal structure: Equivalent effect of alkoxy group?

Consider a structure like this, R - Cy - Cy - Ph - OR' where Cy represents a cyclohexane ring, Ph is a phenyl ring, and R, OR' is alkyl group and oxygen bonded to different alkyl group. If 2 ...
Baklava Gain's user avatar
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Finding or designing a thermochromic that becomes transparent to NIR at room temperature

Are there known nanoparticles or organic materials that have the following properties: absorb near-infrared light and convert them to heat at temperatures below a certain threshold become mostly ...
Heye's user avatar
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When C2 axis of symmetry is present then is the compound meso?

If suppose a compound has C2 axis of symmetry then is it confirmed that the compound will be meso or it can have an enantiomeric pair? And which of following conditions are sufficient enough to ...
Garv Chaudha's user avatar
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When does the angle between the planes in tetrahedral molecule with central atom deviate from 90°?

Consider an atom X bonded to four other atoms A, B, C, D in a tetrahedral fashion with sp³ hybridisation. If A, B, C, D are the same, every bond angle is 109.47°, and the angle between the planes ...
Ritil's user avatar
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What are the limitations of the D, L system and the (+), (-) system for naming organic compounds

In organic chemistry, both the D, L system and the (+), (-) system are widely used, in conjunction with the modern (R, S) system. The D, L system names an organic molecule based on the direction that ...
seamos's user avatar
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What is the meaning of pi selectivity?

I came across this term while going through a research paper for the first time of organic chemistry on diastereoselectivity of tricyclo[,5]pentan-3-ones. I am not familiar with the term and ...
Nyx_Valatoria's user avatar
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Are centre of symmetry(COS) and alternate axis of symmetry(AAOS) dependent on each other?

COS=Centre of symmetery AAOS=Alternate axis of symmetry Lets suppose a molecule has a COS. Does it need to have AAOS? What about the converse? If a molecule has AAOS does it necessarily have a COS? ...
-1 votes
1 answer

How exactly are mirror images of molecules rotated to determine enantiomeric pair?

I know there are many similar questions to this but none could clear my confusion over how exactly the mirrored molecules is rotated i.e on which axis it is rotated to superpose with the original ...
ADITYA DAS's user avatar