1. The First 100 Years of Quantum Physics
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

2. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of
Atoms
Molecules
Nuclei
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

3. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Atoms
Hydrogen Atom
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
The concept of orbits has been replaced by that of wave function orbitals.
A complete set of compatible observables:
Energy (n)
Total angular momentum squared (ℓ)
One (any) component of angular momentum (μ)
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

4. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Atoms 1 2
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei H He
NB: The circular orbits are only meant to be simplistic depictions of electron wave function “orbitals.” 10 3
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College Li Ne

5. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Atoms
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
The Pauli Exclusion Principle explains the chemical properties of all the elements.
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

6. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Atoms
Valence Electron
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei 11 12
Chemistry is the result of vacancies in the outer orbitals of atoms that can be filled with valence electrons from other atoms.
Electron Vacancy
(hole) Na Mg
At this point, things get complicated. The
states are filled before the
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

7. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Atoms
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
The Pauli Exclusion Principle explains the chemical properties of all the elements.
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

8. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Molecules
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei H H
The Hydrogen molecule is formed by covalent bonding. H2
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

9. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Molecules
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
The Hydrogen molecule at actual nuclei separation of 0.734Å H2
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

10. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Molecules
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
NB: Sodium (Na) has a valence of 1. Chlorine (Cl) has a valence of -1. Na Cl
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College
Electrically neutral atoms

11. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Atoms
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
The Pauli Exclusion Principle explains the chemical properties of all the elements.
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

12. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Molecules
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
Salt (sodium chloride) is an example of ionic bonding. Na + Cl _
Ionized Sodium and Chlorine
Salt
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

13. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Nuclei
The nucleons
Charge
Mass
Lifetime
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei n
1838.7
880 sec
neutron p +1
1836.1
> 1031 yrs
Nuclei are composed of neutrons and protons
proton
The electron e -1 1
> 1027 yrs
 Charge is given in units of the electron’s charge magnitude.
Mass is given in terms of the electron’s mass.
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College
Lifetime is given as the mean (or average) lifetime.

14. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Nuclei
Nuclei
Atomic Number
Number of
protons
Atomic Weight
Number of
nucleons
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
Hydrogen p 1 1
Ordinary Hydrogen
Each element has many different nuclei, of same atomic number, called isotopes n p 1 2
Deuterium n p 1 3
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College
Tritium

15. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Nuclei
THE FOUR FUNDAMENTAL FORCES IN NATURE
Relative Strength
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
Gravity
Electromagnetic
At higher energies, this classification requires some modification for the weak and strong nuclear forces.
Weak Nuclear n p
Strong Nuclear
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

16. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Nuclei
Charge Independence Hypothesis:
Considering only the strong force, protons and neutrons are identical
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
Example: Heavy hydrogen – “deuteron” p n p n
Charge independence has its basis in the Standard Model of quarks.
Why do the di-proton and di-neutron not exist in nature?
The answer lies in the Pauli exclusion principal and a new intrinsic quantized observable.
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

17. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Nuclei
Nuclear Spins
INDIVIDUAL SPIN
TOTAL SPIN
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
S s
S s p
Two nucleons (Fermions) combined give us a Boson (spin 1 or 0) n
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

18. is not strong enough to bind nucleons when I = 1!
The First 100 Years of
Quantum Physics
The Quantum Theory of Nuclei
Isotopic Spin (isospin)
INDIVIDUAL ISOSPIN
TOTAL ISOSPIN
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
I i
I i p p n p
Isotopic spin obeys the same mathematical rules as spin. n n
Isotopic spin is an intrinsic
observable related to the particle’s electric charge. n p
With charge independence, the strong nuclear force is independent of the value of i. The strong force
is not strong enough to bind nucleons when I = 1!
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

19. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Nuclei
I i
I i
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei p p n n p
Isospin can be used to describe heavier nuclei. n p n p
He-3 n p n
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College
H-3

20. The Quantum Theory of Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Nuclei
Isospin mirror
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
Isospin images should have the same energy level structure.
25Mn51
26Fe51
26Fe51
Iron and Manganese are
isospin mirror images
25Mn51
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

21. The Quantum Theory of Atoms, Molecules and Nuclei
The First 100 Years of
Quantum Physics
The Quantum Theory of Nuclei 26 25
Lecture 7
The Quantum Theory of Atoms, Molecules and Nuclei
The energy levels of these two mirror nuclei match almost exactly. Small differences are due to the much weaker electrical forces between protons.
Nuclear energy levels for Iron-51 and Manganese-51
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

22. Weird Quantum Goings On
The First 100 Years of
Quantum Physics
Spooky Quantum Goings On
Tunneling
Entangled States
Schrödinger’s Cat
Lecture 8
Weird Quantum Goings On
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

23. Weird Quantum Goings On
The First 100 Years of
Quantum Physics
Quantum Tunneling
Lecture 8
Weird Quantum Goings On
Quantum mechanical tunneling is responsible for many natural phenomena and important technologies.
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

24. Weird Quantum Goings On
The First 100 Years of
Quantum Physics
Quantum Tunneling
Lecture 8
Weird Quantum Goings On
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

25. Weird Quantum Goings On
The First 100 Years of
Quantum Physics
Quantum Tunneling
Examples of Tunneling
Lecture 8
Weird Quantum Goings On
Scanning tunneling micrograph
Tunneling accounts for the basic function of transistors, for some nuclear decays and many other applications.
Transistor
Alpha decay
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

26. Weird Quantum Goings On
The First 100 Years of
Quantum Physics
Quantum Entanglement
Entangled States
Lecture 8
Weird Quantum Goings On
Total Spin = 0 A B
z - axis
Entangled states yield probabilities of obtaining the various possibilities upon measurement. A B A B
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

27. Weird Quantum Goings On
The First 100 Years of
Quantum Physics
Quantum Entanglement
Entangled States
Total Spin = 0
z - axis A B
Lecture 8
Weird Quantum Goings On B A -
Entangled states introduce the very act of measurement into the interpretation of quantum mechanics.
Bob
If Alice measures the z component of photon A’s spin and gets →, then she will know for sure that Bob would measure B’s as ←. And vice versa.
So what? They were probably that way from the start.
But…Alice could just as well have measured the y component of the spin and gotten an exact value. This would violate the uncertainty principle for Sy and Sz.
Alice
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

28. Weird Quantum Goings On
The First 100 Years of
Quantum Physics
Quantum Entanglement
Lecture 8
Weird Quantum Goings On
Schrödinger’s Cat is a famous quantum paradox parable.
Cat in a box with a radioactive atom and a bottle of cyanide gas
If the atom decays, the emitted alpha particle is detected by a Geiger counter.
The electrical signal from the Geiger counter trips a relay.
The relay activates a hammer which breaks the glass bottle.
The cat perishes.
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

29. Weird Quantum Goings On
The First 100 Years of
Quantum Physics
Quantum Entanglement
Lecture 8
Weird Quantum Goings On
Before we look in the box, is the cat alive, dead or both?
Ψ = χatom(whole)φcat(alive) + χatom(decayed)φcat(dead)
The Schrödinger cat fable depends upon the entangled state maintaining its integrity. But for systems for which Planck’s constant is extremely small, this is literally unlikely. Otherwise, we would have much more startling phenomena than an entangled cat state.
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

30. The First Hundred Years
The First 100 Years of
Quantum Physics
The First Hundred Years
of Quantum Physics
Next Term:
The Quantum Physics of Conductors
Semiconductors and Integrated Circuits
White Dwarfs and Neutron Stars
Bose-Einstein Condensates
Relativistic Quantum Electrodynamics
Quantum Field Theory
Quantum Entanglement and EPR
John Bell and Bertelman’s Socks
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College

31. The First Hundred Years
The First 100 Years of
Quantum Physics
The First Hundred Years
of Quantum Physics
Next Term:
The Quantum Physics of Conductors
Semiconductors and Integrated Circuits
White Dwarfs and Neutron Stars
Bose-Einstein Condensates
Relativistic Quantum Electrodynamics
Quantum Field Theory
Quantum Entanglement and EPR
John Bell and Bertelman’s Socks
The Emeritus College
Dr. Richard J. Jacob
Professor Emeritus of Physics
Arizona State University
The Emeritus College