Reaction Rates
Question: Given the microscopic complexity of chemical
reaction mixtures, how can we hope to appropriately
quantify the rate of a reaction?
CHE 372: Mechanisms
1
Equilibrium reaction rates
Consider an elementary reaction (i.e. one occurri
Kinetic-Molecular Theory
Question: Can we attempt to calculate chemical reaction
rates from only theoretical considerations, and if so,
how?
CHE 372: K-M theory
1
Kinetic-molecular theory
Imagine an ideal gas particle moving in a 3-d container
Pressure
Phase Equilibria
Question: How do we describe the standard state of a
substance or mixture under various conditions?
CHE 372: Phase equilibria
1
Phase equilibria
Phase diagram
Plot showing the thermodynamically stable state of a
substance or mixture un
Statistical Mechanics
Question: We can calculate mean energies and heat
capacities from the quantum states of atoms and
molecules; can we calculate other thermodynamic
quantities?
CHE 372: Partition functions
1
Statistical mechanics
Statistical mechanic
The Boltzmann Distribution
Question: If a QM system has a number of quantized
levels, how do we know what states the system is
actually in?
CHE 372: Partition functions
1
The Boltzmann distribution
There are many (hypothetically an infinite number) of
r
Spectroscopy
Question: How do we know virtually everything we know
about atoms and molecules?
CHE 372: Spectroscopy
1
Rotational spectroscopy
Rotational spectra: measure the differences between
quantum levels for a rotating body
Rotational quantization
Approximation Methods
Question: what do the orbitals in the system of the allyl
radical (C3H5) look like, and what are their energies?
CHE 372: MO theory
1
Variational principle
Use one (or more) optimizable parameters to find an
upper limit on the ener
CHE 372, Spring 2014
HW 3
Due 3/10/14
1. What are the symmetries of the vibrations of ethylene chloride (CH Cl ,
is/are potentially IR and/or Raman active?
)? Which of them
The reducible representation is
15
1
3
3
The irreducible representation contributi
CHE 372, Spring 2014
HW 2
Due 2/28/14
1. Determine the point groups to which the following molecules/objects belong:
a) A human being (assuming his/her body are perfectly left-right symmetric)
(only one symmetry plane)
b) A baseball (ignore the directions
CHE 372, Spring 2014
HW 1
Due 2/19/14
1. Use the function
, 0 as a trial wavefunction for the H atom. What is the minimum
energy of the trial wavefunction?
Solution:
The given trial function depends only on , so we can ignore the angular dependence of the
CHE 372, Spring 2014
Exam 1
1. Consider anthracene:
a. (4 points) Set up the secular determinant for the system of anthracene using Hckel theory
Using the numbering scheme
the secular determinant is
b. (5 points) Solve the secular determinant for the ener