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  • Lea Cornelio 2:45 pm on May 15, 2017 Permalink | Reply
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    Fourier Transform in X-ray Crystallography 

    A Fourier transform is performed when a monochomatic X-ray diffracts off a crystal. When the incidence angle is varied, the complete transform is produced.

    The diffraction corresponding to a diffraction vector s and a single electron at position r multiplies the amplitude of the scattered wave by a phase factor e^(−2πirs). If ρ(r) is the electron density function in the crystal, the effect on s will sum to

    F(s)=∫crystal ρ(r)e(−2πirs) dr.

    Therefore, structure factor F(s) appears as the Fourier transform of the electron density function ρ(r).

    How a monochromatic plane wave performs Fourier analysis on the electron density distribution:

    Reference:
    http://www.ams.org/samplings/feature-column/fc-2011-10

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  • Lea Cornelio 3:10 pm on February 18, 2017 Permalink | Reply
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    Symmetries of Spacetime 

    The symmetries of spacetime are collectively called the Poincare symmetry. Particles are irreducible representations of the Poincare group which means that they change in ways governed by Poincare symmetry. The subset of Poincare symmetry that is formulated to automatically obey the symmetries of Einstein’s special relativity is called the Lorentz symmetry. It deals only with rotations and change of inertial frames. Quantum fields, which “give rise” to particles, are irreducible representations of the Lorentz group.

    Reference:
    http://www.quantumdiaries.org/2009/09/20/symmetry-in-physics-part-1-spacetime-symmetry/

     
  • Lea Cornelio 7:06 pm on February 2, 2017 Permalink | Reply
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    Molecular Polarity 

    The polarity from each bond between atoms of different electronegativity and the shape of the molecule can be used to determine the overall polarity of molecules with more than one bond. Each bond’s dipole moment can be treated as a vector quantity with a magnitude and direction. Therefore, the molecular polarity results from the vector sum of the individual bond dipoles.

    Molecular Polarity of CHCl3 (Chloroform)
    mpolarity

    References:
    https://opentextbc.ca/introductorychemistry/chapter/molecular-shapes-and-polarity-2/
    http://chemistry.bd.psu.edu/jircitano/polar.html

     
  • Lea Cornelio 8:08 pm on January 19, 2017 Permalink | Reply
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    Hola Patola 

    What’s your name?
    I’m Lea Katrina Cornelio. You can call me Lea.

    What were your thoughts when you enrolled in this course?
    “I heard frightening stories about this class…”
    “Yaay Sir Paul”

    I also expected that there will be a lot of math in this class so I considered this as one of the classes I will be allotting quite a huge amount of time.

    How comfortable are you with math?
    I understand the discussions most of the time but I need a lot of practice in order to answer exam questions and problem sets. From my previous math classes, I observed that just listening to the discussion isn’t enough for me to retain it. I always need some practice first to get a mastery of the topic.

    What’s your dominant feeling right now?
    sleepy

     
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