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Imagine a container (chamber) into which a sample is placed that is to be
studied. This chamber needs to be evacuated. Discuss possible reasons for this.
Imagine a container (chamber) into which a sample is placed that is to be
studied. This chamber need...
To remove the gas particles that would shorten the mean-free path of the particle used to study the surface.
Describe flash Desorption spectroscopy
Describe flash Desorption spectroscopy
Desorption always has to be activated. A physisorbed particle vibrates in its shallow potential well, and might shake itself off the surface after a short time. The basic observation is a surge in desorption rate (as monitored by a mass spectrometer) when the temperature is raised linearly to the temperature at which desorption occurs rapidly, but once the desorption has occurred there is no more adsorbate to escape from the surface, so the desorption flux falls again as the temperature continues to rise.
Briefly describe two quenching methods that can be used to stop the reaction
after it has been allowed to proceed for a certain time.
Briefly describe two quenching methods that can be used to stop the reaction
after it has been allow...
1. Chemical quench flow method, the reaction is quenched by another reagent,
 such as solution of acid or base.
2. The freeze quench method, the reaction is quenched by cooling the mixture
 within milliseconds.
Discuss the correspondence principle and provide one examples.
Discuss the correspondence principle and provide one examples.
It states that in the limit of very large quantum numbers quantum
mechanics merges with classical mechanics.

An example is a molecule of a gas in a box. At room temperature, the
particle-in-a-box quantum numbers corresponding to the average
energy of the gas molecules are extremely large; consequently the
separation between the levels is relatively so small (n is always small
compared to n 2 ) that the energy of the particle is effectively continuous,
just as in classical mechanics.

As the mass of the particle increases to macroscopic values, the
separation between the energy levels approaches zero. The
quantization disappears. Tennis balls do not show quantum
mechanical effects.

When examining the wavefunction for large values of the quantum
numbers, the probability density becomes uniform over the path of the
motion, which is again the classical result.
Describe why the powder pattern for potassium chloride resembles that of
primitive cubic lattice?
Describe why the powder pattern for potassium chloride resembles that of
primitive cubic lattice?
The powder pattern/reflections look very much like those from a simple cubic
structure because the scattering power of the potassium ion is almost exactly
equal to that of the chloride ion, since both ions have the argon electronic
structure. A more accurate determination of the intensities of reflections shows
that potassium chloride does indeed form a face-centered cubic lattice.