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Introduction: Quantum Mechanics, Schrödinger, Hydrogen atom. Spectra

   

This plate is from a discussion - based on some earlier lectures. It turns our attention to general problems,
in contrast to those which can be solved analyticaly.
When general problems are solved - numerically - the differences between the two fields appear in the sketched perspective.

Classical physics - system of ordinary ( and in fact 1. order )  differential equqtions
Quantum physics - allways over the whole space. And as mentioned in the next plate - complex numbers are essential

Also sketched is a qualitative way to Schrödinger equation: from de Broglie's assumptions to Schrödinger's construction.

No energy concept in Newton's time - see e.g. https://en.wikipedia.org/wiki/Conservation_of_energy   
        https://en.wikipedia.org/wiki/Vis_viva       It is energy in Quantum Mechanics ( or the Hamiltonian )

      0005_Classical-Quantum.png

       0005_Classical-Quantum.png


Born's idea about probability density  <--  from wavefunction is the cornerstone of quantum physics.
Time dependent  Schrödinger equation   vs.  Stationary problems ( time and space variable separation )

      0010_Probability_Schrodinger.png

       0010_Probability_Schrodinger.png


Historically - allowed energies - explained the spectra.
Here is a little exercise showing the relation between  ENERGY LEVEL DIAGRAM    and   ENERGY SPECTRUM
      Historically it was wavelength  spectrum - but Planck's work had shown the relation between energy and frequency (ant thus wavelength )
What we have demonstrated below: if you know the spectrum - you still do not know the energy levels
      in the lowest part of this plate is demonstrated that the same spectrum is consistent with both of the LEVEL DIAGRAMS
      0020_Levels_and_spectrum.png

       0020_Levels_and_spectrum.png

Above:         the lowest part of the above plate demonstrated that the same spectrum is consistent with both of the LEVEL DIAGRAMS
-------------

So why are there only certain allowed energies?
          In one dimensional cases - for wrong energies the solution will "blow up" at infinity (also in 2-dim and 3-dim, but more complicated)

Only for some energies the solutions vanish outside of the attractive region   (  Hurrah when we hit .... )
      0030_Eigenenergies.png

       0030_Eigenenergies.png

Above: lower part  - Coulomb problem = Hydrogen atom - like    Note the two forms - two "systems of units"
                                                                                                      ( more about Gauss and SI later .... )

The good and bad solutions - in Schrödinger Toy Program (browser application)   http://folk.uib.no/nfylk/PHYSTOYS/schroed/

      0035_Schrodingers_Toy.png

       0035_Schrodingers_Toy.png

Getting to the good energy and good solution:  - in Schrödinger Toy Program (browser application)   http://folk.uib.no/nfylk/PHYSTOYS/schroed/


                                                                            Playing_with_Schrodinger_Toy.png

Above:   Playing with Schrödinger's Toy - snapshots. Question: HOW IS THE ENERGY CHANGING from left to right
                                                                                                     DECREASING    or  INCREASING   ?????

Below: Kinetic energy operator  - from momentum operator - gradient - Laplace operator -  SPHERICAL COORDINATES

      0040_Radial_Coordinates.png

       0040_Radial_Coordinates.png


LAPLACE OPERATOR  - Spherical coordinates   Separation of Variables 
https://en.wikipedia.org/wiki/Laplace_operator#Three_dimensions

      0050_laplace_operator.png

       0050_laplace_operator.png


Additional snapshot: What also can be done with Schrödinger's Toy - Simple resonances


       Playing_MORE_Schrodinger_Toy

Next time:    Continue the work with
                                    LAPLACE OPERATOR  - Spherical coordinates   Separation of Variables 
                                    More on hydrogen and experiments (and some historical facts)
                                    Visualization of the "orbitals"


visit the last years' pages (open in new windows or tabs)
                               http://folk.uib.no/nfylk/PHYS261/2015_08_20/      (See the levels database there, cf below)
                               http://folk.uib.no/nfylk/PHYS261/2015_08_26/
                               http://folk.uib.no/nfylk/PHYS261/2014_08_19/
                               http://folk.uib.no/nfylk/PHYS261/2014_08_21/
                               http://folk.uib.no/nfylk/PHYS261/2014_08_26/        ( especialy the "Atomic Units part)

  We also mentioned this (see the details in the first link above)
      Level and lines diagrams from http://physics.nist.gov/PhysRefData/ASD/lines_form.html
      This diagram requires Java in the browser, at present de-popularized due to possible security problems
       when used on untrusted sites  ( we can trust NIST  - http://www.nist.gov)
      The atomic database: http://www.nist.gov/pml/data/asd.cfm
 

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