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10 Cards in this Set
- Front
- Back
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Using the spring analogy, when are there no vibrations?
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When the spring is stationary at equilibrium. This is its lowest potential energy.
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Using the spring analogy, how do you add potential energy?
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By stretching or compressing the spring.
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Using the spring analogy, what is the name of the force which brings the spring back to its former shape?
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Restoring force
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If you look at the vibration of a molecule with a single bond and then one with a double bond do you expect the Vib freq to increase or decrease?
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The vibrational frequency increases. This is because the "spring" is wound tighter.
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If you were to replace the atoms on the end of the spring with heavier atoms what would happen to the Vib freq?
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The vibrational frequency decreases.
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If you were to plot a graph showing the potential energy of a bond against bond length (i.e. imagine the bond is vibrating) what shape would the graph take?
(Hint: P.......) |
Parabolic
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What is the equation associated with the harmonic oscillator?
(Hint: Ev = ) (Hint 2: Remember no correction this time) |
Ev = hwe(v+1/2)
v = vibrational quantum number we = vibrational frequency Ev = vibrational energy |
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In the harmonic oscillator are the energy levels evenly spaced or do they get closer together?
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Evenly spaced
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What is the equation for the relationship between vibrational frequency (we) and the force constant (k)?
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we = (1 / 2π) √ (k / μ)
k = force constant μ = reduced mass |
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What are the limitations of the harmonic oscillator model?
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The infinite set of energy levels suggests an infinite energy well. If this were the case then bonds between atoms would never break, hence the creation of the anharmonic oscillator model.
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