extremely fine or thin, as in a spectral line split into two or more components
— Doing this results in the emission or absorption of a photon with energy
˜v = 4E
hc
(1.5)
Failure of the Bohr model
• No fine structure predicted (electron-electron coupling)
• No hyperfine structure predicted (electron-nucleus coupling)
• No Zeeman effect predicted (response of spectrum to magnetic field)
20
• Spin is not included in theory
The Bohr quantization idea points to a wavelike behavior for the electron.
• Therefore atomic orbitals must be quantized.
r =
4π0N2~2
Zmee2 (1.1)
where Z is the atomic number, me and e are the mass and charge of the
electron respectively and 0 is the permittivity of free space.
of or relating to a quantum or capable of existing in only one of two states
• Therefore atomic orbitals must be quantized.
r =
4π0N2~2
Zmee2 (1.1)
where Z is the atomic number, me and e are the mass and charge of the
electron respectively and 0 is the permittivity of free space.
(chemistry) the ratio of concentrations when equilibrium is reached in a reversible reaction (when the rate of the forward reaction equals the rate of the reverse reaction)
the act of dividing into quanta or expressing in terms of quantum theory
— Doing this results in the emission or absorption of a photon with energy
˜v = 4E
hc
(1.5)
Failure of the Bohr model
• No fine structure predicted (electron-electron coupling)
• No hyperfine structure predicted (electron-nucleus coupling)
• No Zeeman effect predicted (response of spectrum to magnetic field)
20
• Spin is not included in theory
The Bohr quantization idea points to a wavelike behavior for the electron.
the branch of physics that makes theoretical predictions about the behavior of macroscopic systems on the basis of statistical laws governing its component particles
83
III Statistical Mechanics and The Laws of Thermodynamics
88
12 Rudiments of Statistical Mechanics 89
12.1 Statistics and Entropy .
Austrian physicist who discovered the wave equation
11.9 Laidler&Meiser ∗ ∗∗
The must be continuous and single valued
Particles have wave-like characteristics
The Bohr atom was an important step towards the formulation of quantum theory
• Erwin Schrödinger (1887—1961): Wave mechanics
• Werner Heisenberg (1902—1976): Matrix mechanics
• Paul Dirac (1902—1984): Abstract vector space approach
21
2.
the lowest energy state of an atom or other particle
(1.2)
Tests of the Bohr atom
• Ionization energy of Hydrogen atoms
— The Ionization energy for Hydrogen atoms (Z = 1) is the minium
energy required to completely remove an electron form it ground state,
i.e.,
an aerial half a wavelength long consisting of two rods connected to a transmission line at the center
Flaws of the solar system model
• Newton: OK √
• Maxwell: problem √
17
— As the electron orbits the nucleus, the atom acts as an oscillating dipole
• — The classical theory of electromagnetism states that oscillating dipoles
emit radiation and thereby lose energy.
the branch of quantum physics that accounts for matter at the atomic level; an extension of statistical mechanics based on quantum theory (especially the Pauli exclusion principle)
Contents
I Basic Quantum Mechanics 15
1 Quantum Theory 16
1.1 The “Fall” of Classical Physics .
Austrian physicist who discovered the wave equation
11.9 Laidler&Meiser ∗ ∗∗
The must be continuous and single valued
Particles have wave-like characteristics
The Bohr atom was an important step towards the formulation of quantum theory
• Erwin Schrödinger (1887—1961): Wave mechanics
• Werner Heisenberg (1902—1976): Matrix mechanics
• Paul Dirac (1902—1984): Abstract vector space approach
21
2.
11.9 Laidler&Meiser ∗ ∗∗
The must be continuous and single valued
Particles have wave-like characteristics
The Bohr atom was an important step towards the formulation of quantum theory
• Erwin Schrödinger (1887—1961): Wave mechanics
• Werner Heisenberg (1902—1976): Matrix mechanics
• Paul Dirac (1902—1984): Abstract vector space approach
21
2.
any property used to characterize matter and energy and their interactions
The Average Value Theorem
Postulate III implies that if ψ is an eigenfunction of a particular operator representing
a physical observable, then all measurements of that physical property
will yield the associated eigenvalue.
quantity of protons in the nucleus of an atom of an element
• Therefore atomic orbitals must be quantized.
r =
4π0N2~2
Zmee2 (1.1)
where Z is the atomic number, me and e are the mass and charge of the
electron respectively and 0 is the permittivity of free space.
(1.2)
Tests of the Bohr atom
• Ionization energy of Hydrogen atoms
— The Ionization energy for Hydrogen atoms (Z = 1) is the minium
energy required to completely remove an electron form it ground state,
i.e.,
English theoretical physicist who applied relativity theory to quantum mechanics and predicted the existence of antimatter and the positron (1902-1984)
11.9 Laidler&Meiser ∗ ∗∗
The must be continuous and single valued
Particles have wave-like characteristics
The Bohr atom was an important step towards the formulation of quantum theory
• Erwin Schrödinger (1887—1961): Wave mechanics
• Werner Heisenberg (1902—1976): Matrix mechanics
• Paul Dirac (1902—1984): Abstract vector space approach
21
2.
(1.2)
Tests of the Bohr atom
• Ionization energy of Hydrogen atoms
— The Ionization energy for Hydrogen atoms (Z = 1) is the minium
energy required to completely remove an electron form it ground state,
i.e.,
the presence of groups of closely spaced spectrum lines observed in the atomic spectrum of certain elements
— Doing this results in the emission or absorption of a photon with energy
˜v = 4E
hc
(1.5)
Failure of the Bohr model
• No fine structure predicted (electron-electron coupling)
• No hyperfine structure predicted (electron-nucleus coupling)
• No Zeeman effect predicted (response of spectrum to magnetic field)
20
• Spin is not included in theory
The Bohr quantization idea points to a wavelike behavior for the electron.
To
solve this problem it is useful to define the set of three dimensional column vectors
V (j) such that the three elements are the total number of allowed configurations of
a j-atom chain having the jth atom in state A, B or C. For example,
V (1) =
⎡
⎢⎣
1
1
1
⎤
⎥⎦
, V (2) =
⎡
⎢⎣2
3
2
⎤
⎥⎦
, V (3) =
⎡
⎢⎣
5
7
5
⎤
⎥⎦
, · · · .
a physical force produced from the interaction of charged particles
Flaws of the solar system model
• Newton: OK √
• Maxwell: problem √
17
— As the electron orbits the nucleus, the atom acts as an oscillating dipole
• — The classical theory of electromagnetism states that oscillating dipoles
emit radiation and thereby lose energy.
switch for reversing the direction of an electric current
The general statement of the Heisenberg uncertainty principle is
δαδβ ≥
1
2
¯¯¯
Dh
ˆα,ˆβ
iE¯¯¯ , (3.13)
where the notation
h
ˆα,ˆβ
i
means the commutator of ˆα and ˆβ.
an enclosure within which something originates or develops
(23)
The V (j+1) can be found from the V (j) vector using the matrix equation,
V (j+1) = MV (j), (24)
where for this example
M =
⎡
⎢⎣
1 1 0
1 1 1
0 1 1
⎤
⎥⎦
.
— Doing this results in the emission or absorption of a photon with energy
˜v = 4E
hc
(1.5)
Failure of the Bohr model
• No fine structure predicted (electron-electron coupling)
• No hyperfine structure predicted (electron-nucleus coupling)
• No Zeeman effect predicted (response of spectrum to magnetic field)
20
• Spin is not included in theory
The Bohr quantization idea points to a wavelike behavior for the electron.
a reddish oxide of lead (Pb3O4) used as a pigment in paints and in glass and ceramics
(1.2)
Tests of the Bohr atom
• Ionization energy of Hydrogen atoms
— The Ionization energy for Hydrogen atoms (Z = 1) is the minium
energy required to completely remove an electron form it ground state,
i.e.,
(physical chemistry) the pressure exerted by a solution necessary to prevent osmosis into that solution when it is separated from the pure solvent by a semipermeable membrane
Flaws of the solar system model
• Newton: OK √
• Maxwell: problem √
17
— As the electron orbits the nucleus, the atom acts as an oscillating dipole
• — The classical theory of electromagnetism states that oscillating dipoles
emit radiation and thereby lose energy.
— Eionize experimentally observed from spectroscopy is 13.605 eV (very
good agreement)
• Spectroscopic lines from Hydrogen represent the difference in energy between
the quantum states
— Bohr theory: Difference energies
Ej − Ek =
e2
2a0
μ
1
N2
j −
1
N2
k
¶
= R
μ
1
N2
j −
1
N2
k
¶
(1.4)
Initial state Nk Final States Nj Series Name
1 2,3,4,· · · Lyman
2 3,4,5,· · · Balmer
3 4,5,6,· · · Pachen
4 5,6,7,· · · Brackett
5 6,7,8,· · · Pfund
• — Since the orbita...
To
solve this problem it is useful to define the set of three dimensional column vectors
V (j) such that the three elements are the total number of allowed configurations of
a j-atom chain having the jth atom in state A, B or C. For example,
V (1) =
⎡
⎢⎣
1
1
1
⎤
⎥⎦
, V (2) =
⎡
⎢⎣2
3
2
⎤
⎥⎦
, V (3) =
⎡
⎢⎣
5
7
5
⎤
⎥⎦
, · · · .
Solution: Here we either remember an identity or turn to our handout of partial
derivative identities to employ the cyclic rule to
¡∂P
∂T
¢
V :
μ
∂P
∂T
¶
V
= −
μ
∂P
∂V
¶
T
μ
∂V
∂T
¶
P
.
— Eionize experimentally observed from spectroscopy is 13.605 eV (very
good agreement)
• Spectroscopic lines from Hydrogen represent the difference in energy between
the quantum states
— Bohr theory: Difference energies
Ej − Ek =
e2
2a0
μ
1
N2
j −
1
N2
k
¶
= R
μ
1
N2
j −
1
N2
k
¶
(1.4)
Initial state Nk Final States Nj Series Name
1 2,3,4,· · · Lyman
2 3,4,5,· · · Balmer
3 4,5,6,· · · Pachen
4 5,6,7,· · · Brackett
5 6,7,8,· · · Pfund
• — Since the orbita...
Finally for the last function it is best to used Euler’s identity and write
e−2ix = cos2x + i sin 2x (1)
The real part of this function, cos 2x, has a period of π as does the imaginary
part, sin 2x.
a quality that distinguishes between similar things
Solve the Schrödinger equation, Hˆ ψ = Eψ, which is now a second order
differential equation of the form
∙
−~2
2m ∇2 + V (x, y, z)
¸
ψ = Eψ
⇒ −~2
2m ∇2ψ + (V (x, y, z) − E) ψ = 0 (3.8)
28
• Note: It is solely the form of V (x, y, z) which determines whether this
is easy or hard to do.
(29)
Problem: Using the classical theory of light scattering, calculate the positions of
the Rayleigh, Stokes and anti-Stokes spectral lines for benzene.
an optical device that produces an intense beam of light
Assume benzene
has only two active modes (992cm−1 and 3063cm−1) and assume the Laser light
used to do the scattering is at 20000cm−1 (this is 500nm–green light).
• The kinetic energy is always of the form
T =
1
2m
¡
p2
x + p2y
+ p2z
¢
(3.3)
• The potential energy is almost always a function of coordinates only
V = V (x, y, z) (3.4)
• Note: Some quantumsystems don’t have classical analogs so the Hamiltonian
operator must be hypothesized.
the lines of force surrounding a permanent magnet or a moving charged particle
— Doing this results in the emission or absorption of a photon with energy
˜v = 4E
hc
(1.5)
Failure of the Bohr model
• No fine structure predicted (electron-electron coupling)
• No hyperfine structure predicted (electron-nucleus coupling)
• No Zeeman effect predicted (response of spectrum to magnetic field)
20
• Spin is not included in theory
The Bohr quantization idea points to a wavelike behavior for the electron.
331
Chemistry 351: Physical
Chemistry I
1
1
Solved Problems
I make-up most of the problems on the problems sets, so it might be helpful to
you to see some of these problems worked out.
a particular course of action intended to achieve a result
Solution: Following our general procedure from the notes if we have some unnormalized
wavefunction, ψunnorm we know that this function must simply be some
constant N multiplied by the normalized version of this function:
ψunnorm = Nψnorm (8)
We have shown generally that N is given by
N =
sZ
space |ψunnorm(x)|2 dx.
The “Fall” of Classical Physics
A good theory:
• explain known experimental results
• self consistent
• predictive
• minimal number of postulates
Around the turn of the century, experiments were being performed in which the results
defied explanation by means of the current understanding of physics.
The Heisenberg Uncertainty Principle
In quantum mechanics certain pairs of variables can not, even in principle, be
simultaneously known to arbitrary precision.
Flaws of the solar system model
• Newton: OK √
• Maxwell: problem √
17
— As the electron orbits the nucleus, the atom acts as an oscillating dipole
• — The classical theory of electromagnetism states that oscillating dipoles
emit radiation and thereby lose energy.
of or relating to or caused by attraction for iron
— Doing this results in the emission or absorption of a photon with energy
˜v = 4E
hc
(1.5)
Failure of the Bohr model
• No fine structure predicted (electron-electron coupling)
• No hyperfine structure predicted (electron-nucleus coupling)
• No Zeeman effect predicted (response of spectrum to magnetic field)
20
• Spin is not included in theory
The Bohr quantization idea points to a wavelike behavior for the electron.
a group of symbols that make a mathematical statement
Qcrystal = qN
HO =
Ã
1
2 sinh β~ω
2
!
(30)
From our formulas for statistical thermodynamics
A = −kT ln Qcrystal = +NKT ln
μ
2 sinh
β~ω
2
¶
, (31)
where we used properties of logs to pull the N out front and move the sinh term
from to the numerator,
S = −kβ
∂Qcrystal
∂β
+ k ln Qcrystal (32)
=
N kβ~ω
2
coth
β~ω
2 − k ln
μ
2 sinh
β~ω
2
¶
and
U = −
∂Qcrystal
∂β
=
N~ω
2
coth
β~ω
2
.
a substance that cannot be separated into simpler substances
To
solve this problem it is useful to define the set of three dimensional column vectors
V (j) such that the three elements are the total number of allowed configurations of
a j-atom chain having the jth atom in state A, B or C. For example,
V (1) =
⎡
⎢⎣
1
1
1
⎤
⎥⎦
, V (2) =
⎡
⎢⎣2
3
2
⎤
⎥⎦
, V (3) =
⎡
⎢⎣
5
7
5
⎤
⎥⎦
, · · · .
Created on Thu Dec 15 17:43:41 EST 2011
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