Supplemental notes on chemical bonding

The variational principle and chemical bonding. These are some scanned notes from when I was an undergrad, related to last Thursday's and today's lectures.

PH253: Public talk

Dr. Orzel has been nice enough to post his slides, so if you were not able to make the lecture, you can complete the extra credit assignment by reading his slides and sample book material. Write a page on what you learned.

PH253: Physics help desk

Good news everyone, I've negotiated with the PH10x TAs, and they have agreed that it is OK if you come by the physics help desk for PH253 homework questions.* You can find the help desk hours here. The following TAs explicitly agreed to help with PH253 questions:

Lei Lu, Zachary Burell, Arindam Das, Jason Carson, Chockalingam Sivakumar, Sahar Keshavarz, Christopher Sterpka, Andrea Chaney

I didn't hear back from a few of the TAs when I asked if it was OK for you to come by, but the list above covers most of the available help desk hours. (I said that a lack of response would be construed as a 'yes' on their part though.) I agreed to send them the HW solutions in advance each week so they can better help you.

*Previously, the help desk was only for 100-level physics, but I asked if they would expand their repertoire.

Public talk this evening

We had a good turn out, I saw quite a few of you there. I though it was a great talk, particularly relevant to what we've been covering lately (down to the fact that he used some of the same images/videos I've posted here). I really liked the football throwing explanation of particle tunneling ... it is important to know your audience.* Thanks for making a good showing for Dr. Orzel!

If you couldn't make either of his lectures today, you can still do the extra credit assignment. The first chapter of his book (and a dramatic reading of chapter 3) are available here. Chapter 1 discusses the wave particle duality (which we spent quite a bit of time on). In lieu of attending the talk, you can read it and write me a page about what you learned from it according to the previous rules. It is a good read, and I highly recommend the whole book. (And no, I don't get anything for saying that, I met Dr. Orzel for the first time today.)

*That's not to say that my brown bottle explanation of tunneling this morning was making a comment about what you do in your spare time, but it seemed like an everyday thing you could all at least imagine, even if lacking the requisite first-hand experience. I clearly need more football-based explanations.

PH253: HW6 is out

Due next Wednesday ...

Also, a nice applet for visualizing wave functions.

PH253: Wave functions

Hyperphysics is good stuff. Good example calculations/solutions and explanations of Schrodinger's equation.

PH253: online grades

I now finally have the system set up so you can log in and see your grades (HW1-3 and Exam 1 right now). Since I am still young enough to be idealistic, I'm using an open source system called Moodle. Apparently you still have to pay if you want a sensible name. Instructions below the jump ...

Double slit applet

A nice applet to illustrate the crazy double slit stuff we talked about today.  You can use photons, electrons, neutrons, and helium atoms, and even use multiple sources or vary the incident wavelength. Note the different modes - high intensity, single particles, and lasers. If you like, add a detector on one or both of the slits and watch the interference go away ... neat stuff.

Also, the actual experiment with single electrons!

PH253 facebook group

Find each other and commiserate. ;-)

Supplemental texts

In case you're wanting to review your E&M or mechanics ...

• Serway & Jewett, "Physics for Scientists & Engineers" Vol 2 (the PH105/106 book). Covers mechanics and E&M
• The Feynman Lectures on Physics (in the library or the physics student lounge on 1st floor). Three volumes, covers mechanics, E&M, and modern physics. I draw on these heavily in preparing lectures.
• E.M. Purcell "Electricity and Magnetism" (should be in library; uses different units!). E&M only, but it has fantastic treatments of moving charges and radiation. The only downside is the use of cgs units, which are almost certainly unfamiliar to you, and which make the formulas look a little different.

Feynman & Purcell are more mathematically sophisticated than Serway, both very casually use of vector calculus. For the most part, though, you should be able to follow the essential points even if you haven't seen some bits of the math.

PH253: applet for tomorrow's lecture

http://webphysics.davidson.edu/applets/retard/Retard_FEL.html

Lets you visualize the field from moving & accelerating charges. Drag the velocity slider to start & stop a charge in an inertial frame (what we'll start with) or set it in simple harmonic motion (SHO, what we'll end with).

Lecture notes for relativity

We'll be starting out with relativity for the first 2-3 classes (Ch. 1 of your text), and you might find some notes I wrote [23Mb PDF] useful as a supplement. The first chapter of the notes covers relativity; the rest should be review, but might still be helpful. The notes are for PH102, but that class actually covers relativity in about the same way (albeit a little less 'mathy').

Also the slides I'll use for Tuesday's first lecture are here.

Link: modern physics lecture notes

There are some nice online lecture notes for a comparable course here.

Homework template

This is the format I'd like you to use for homework problems. You don't have to print out the template exactly, you can just fill out a sheet of paper in the same fashion. The main point is that I'd like to ensure that you're solving problems in a logical, organized way, with clarity and precision. The idea is that at first this will help reinforce a general, systematic approach to problem solving that will serve you well when the material gets harder.

Your homework be graded on the appearance (if applicable) and quality of these items:

• Find/Given - what are you supposed to find, and what have you been given?
• Sketch - try to visualize the problem.
• Relevant equations - identify what basic equations might be of some help.
• Symbolic solution - without using numbers, algebraically find the desired quantity in terms of given quantities.
• Numeric solution - if given, plug in any numbers given. 
• Double check - using dimensional analysis, order-of-magnitude estimation, for example, see if your answer makes sense. In some cases, you might just solve the problem by a completely different technique.

I'll describe this in some detail in class, and will try to follow the template when I'm solving problems in class. The format isn't as restrictive as it might seem at first, a lot of students find that it actually helps them organize their thoughts and get started on a problem that seemed incomprehensible at first.

PH253: Cool laser simulation / Reading

Based on what we talked about today, you should be able to figure out how to make this simulation work ...

Also, today's lectures were based mostly on material from the Feynman lectures:
Volume III, Ch. 4 (Ch. 3 as a reminder)
Volume I, Ch. 42 (Ch. 40, 41 as a reminder)

I also made use of Solymar & Walsh (Ch. 12) for specific examples of laser systems. Again, note the (now 10 part) series on cool laser applications over here.

Amazing laser applications

A (so-far) 9-part series of amazing laser applications.

Coincidentally, we'll figure out how lasers work in Tuesday's lecture. We'll start from where we left of with particle statistics, and figure out the 'stimulated emission' part of the acronym first. Once we have the key bits in place, I'll talk briefly about how one goes about constructing a laser,  and why they are not just fancy flashlights.

Well, they are fancy flashlights, but they do other things too ...

PH253/255

Sodium doublet & spin-orbit coupling information.

Also, hydrogen & deuterium.

Double slit experiment

Cool images/explanation and video of an electron double-slit experiment, courtesy Hitachi. Time-lapse of single-electron microscopy ... does not get much more direct than this. Spooky, but true.

(Some companies still do really cool R&D. More nuggets to be mined on the Hitachi site ...)

Pauli's nobel lecture

Worth a read, and related to current PH253 material. Very much accessible.

Nice pictures of atomic orbitals

One, two, three.