Recent content by abhi2005singh

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    Why different crystal phases have different colours?

    Yes, the chemical surroundings can change the electronic structure. There are other methods as well, like, chemical substitution, change in bond length, bond strength, lattice parameter etc.
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    How Do Atoms Bond Together and What Forces Are Involved?

    No book can possibly explain everything about any kind of bonding. Please do not use the term "Atomic Bonding". There are molecules once there is any kind of bonding.
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    Atomic Shell Theory: Bohr-Sommerfeld model

    There is not much difference between the two. It has been working so far. Do not freak out if someone gives you this answer. This is true with every theory/model. This has already been answered by @DiracRules Most of the theories (if not all) are "fitting formula". If the fitting works for...
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    Atomic Shell Theory: Bohr-Sommerfeld model

    No, it doesn't work well. There are many things which are not explained: http://en.wikipedia.org/wiki/Bohr_model#Shortcomings" This is also not correct. We are not using the atomic orbitals because of the BS model. These orbitals follow from quantum mechanics. Please read what @DiracRules have...
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    Atomic Shell Theory: Bohr-Sommerfeld model

    Well, one can also ask: "How do we know that these orbitals exist for H atom?". The only answer which comes to mind is that they are predicted using theory and that no experimental evidence is available against it. The theory explains well the experimental facts. This is true not only in the...
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    Why different crystal phases have different colours?

    Colors shown by the crystal depend upon various things and are related to the electronic structure and not on the phonon modes. Defects are one of these sources. Change in crystal structure can change the electronic structure of the material and hence the color of the crystal since it is related...
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    How Do Atoms Bond Together and What Forces Are Involved?

    Electromagnetic force. There can be other type of bonds as well depending upon the approach of the researcher/professor. The various bonds are just the models for the EM interaction and hence they should not be taken too seriously, though, they are great to get some physical insight into...
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    Gauss law and infinite spherical charge distribution

    I did found the answer in some other discussion forum. I am sharing it below if someone wants to know: Gauss' law comes from the divergence theorem, which states that the divergence of a vector field integrated over a volume is equal to the vector field itself integrated over the boundary of the...
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    Gauss law and infinite spherical charge distribution

    @ideasrule I understand that it is physically impossible to have an infinite charge distribution. If you are suggesting that since it is physically impossible, so it is not certain that physical laws will hold good, then please support it with proper reasoning. I would only like to address the...
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    Gauss law and infinite spherical charge distribution

    @Quinzio For the sphere with center A and radius R, contribution of the charge distribution outside this sphere will be zero. Due to the remaining spherical charge distribution, electric field will be zero at the center A while non-zero at other points. This is the paradox. What you have given...
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    Gauss law and infinite spherical charge distribution

    Similar (or may be dissimilar) paradox: The electric field due to an infinite sheet of charge (constant surface charge density) is constant, away from the sheet. But what about the electric field at a point "on" the sheet. According to symmetry, there should be no electric field. However as soon...
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    Gauss law and infinite spherical charge distribution

    1. The problem statement Consider an infinite spherical charge distribution with constant charge density. According to symmetry of the problem, I expect the electric field at any point to be zero. But if you construct a Gaussian sphere and apply Gauss theorem, it will give you some finite field...
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    Understanding J Splitting in XPS

    l = 1, s = 1/2, j = |l - s|, ..., l + s = 1/2, 3/2. Hence you have j = 1/2, 3/2 with l = 1 (p). Thus you have terms of 2p1/2 and 2p3/2.
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    What are the charged vacancies

    I am not sure how an O2- ion can be removed from the solid. As far as my understanding goes, when oxygen vacancies are created, it generally leaves behind two electrons in the conduction band. This does not lead to a charged material.
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