## Wednesday, March 31, 2010

I feel like this homework set is coming due a bit too quickly, based on what we covered on Tuesday and what I want to do tomorrow. I'd rather you not rush it, and have some time to understand the problems.

Therefore: the homework deadline is extended until Tuesday, 6 April at midnight. Spread the word ...

### PH253: molecular orbitals

Here's a nice introduction to the variational method and the linear combination of atomic orbitals (LCAO) we were talking about last time. It describes some further approximations that one can use to do calculations on molecular systems, and the level is about the same as our last class (modulo a bit of linear algebra). Those of you in chemistry classes should be able to follow it pretty easily I guess.

### PH253: HW9 hints

Copious hints on HW9 below the fold ...

### PH253: Thursday's plan

Thursday, we'll go over the variational method for bonding again, and do a couple of examples to show you how the method really works. Today (Tuesday) we went over the general scheme for molecular orbitals, we'll expand on that to figure out how simple hydrocarbons and such things work.

From this we'll find the pi and sigma orbitals you've probably heard so much about in Chemistry class, the basis for starting organic chemistry. From there, we'll be able to figure out some methods for handling a whole solid's worth of atoms and the electronics properties of metals, semiconductors, and insulators. With a few more details, next week we'll be calculating the properties of realistic materials.

In other news, I'll be posting some heavy-duty homework hints on Wednesday to get you started, and we'll do a couple of problems in class on Thursday.

## Tuesday, March 30, 2010

### PH253: HW9 omission

In problem number 5, I forgot to give you the dissociation energy ... Ed = 3.37eV. This is corrected in the version of the HW now online.

## Monday, March 29, 2010

### PH253: HW9 is out

Here you go. Mostly about molecules, section 4.2 in your text (and the subject of most of tomorrow's lecture).

## Thursday, March 25, 2010

### PH253: HW is due friday

You know the homework is due on Friday, right? Like it says on both the google calendar and the instructions box on the HW set itself ...

Just wondering, since I seem to be getting a lot of early homework, and I can't stress enough how unusual that is. ;-)

### Scientists versus science fans

There is truth in this. We invented the symbol so we don't have to bother memorizing digits ... just like you solve problem symbolically so you've solved all problems of that class, not just one particular example.

Of course, there is only one digit of pi in base pi. The rest of the numbers are a real pain then, however.

### PH253: office hours the rest of the week

Office hours are going to be tight today owing to a number of unsavory meetings. Best times are:

11-12 in Gallalee
12-2:30 in Bevill

Friday is proving tough as well. Best times are:

11-1 Bevill
3:30-5 Gallalee

I will be reading email continuously though (and catching up on Wednesday's email shortly I hope).

## Wednesday, March 24, 2010

### PH253: Schedule

I've updated the Google calendar to reflect our adapted schedule ... have a look. Clicking on any class event and showing event details will tell you what sections of the book are relevant for that day.

Basically, compared to the original schedule, we are doing more solid state physics + applications and skip the sections on nuclear/particle physics (as it will be covered in the new PH354 'Intermediate Modern Physics' curriculum from now on).

If you'd rather just have a printed schedule, look here. Same information, but you can see it all at once ...

Note that the very last lecture (29 Apr) is partly final exam review, and partly 'viewer's choice' ... that means I'm open to suggestions for what you want the final lecture to be about. Most anything plausibly PH (or CH or ECE or MTE) related is fair game ... give me some suggestions for a topic you think we miss during the semester, and I'll try to prepare a short lecture on it.

## Tuesday, March 23, 2010

### 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 ...)

## Monday, March 22, 2010

### Pauli's nobel lecture

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

## Sunday, March 21, 2010

### PH253: HW8 is out

Here it is. Due on Friday 26 Mar; we'll go over many of these in class. You can find the figures here, for a couple of the problems it might be easier to just draw on the figures.

## Wednesday, March 17, 2010

### PH253: HW5 solutions

At long last, here they are. HW 6-7 solutions following soon, I hope.

## Saturday, March 13, 2010

### Spring Break

Turning in homework at midnight on Friday of spring break: hardcore. Well done.

## Thursday, March 11, 2010

### PH253: notes on hydrogen

I scanned the last 4 or so lectures worth of my own notes and put them online. They cover the radial Schrodinger equation, the states of the hydrogen atom, and spin. Today's stuff starts on page 33, for those (many) of you who were not here today.

One, two, three

## Tuesday, March 9, 2010

### PH253: hints on HW6-7, #1

There is one big issue with this problem: there are lots of shiny numbers that you're just dying to plug in to messy equations. Resist! It is a trap!

### PH253: Hydrogen wavefunctions

Good starter; wavefunctions; probability plots. Hyperphysics is good stuff.

### PH253: Belated HW4 and Exam 1 solutions

Exam solutions, HW4 solutions.

The exam solutions are scanned for now, I hope to rectify that situation this week or over the break. HW5 and the quiz/bonus solutions should be out soon as well ...

## Thursday, March 4, 2010

### Wolfram alpha

If you like the integrator, you'll like Wolfram Alpha. Physics, math, etc. Incidentally, it will do definite integrals numerically, solve cubic equations, and other things useful for the current homework.

Beware, it is a time sink ...

### Hearing uncertainty.

Excellent post demonstrating that you can hear wave uncertainty.

### PH253: Supplemental reading for this week & next

Feynman lectures on physics, volume III, chapter 19. Today we'll cover what's in sections 1-3, which is also covered in your textbook in the appendix to section III.

## Wednesday, March 3, 2010

UPDATE 2: Fixed. Sorry about that ... should not do these things so late at night I guess. Midterm grades on myBama should now be correct.

Moodle grades are now updated. This includes HW1-4, and the exam grade reflects the extra credit from the in-class makeup quiz.* It does not include the extra credit for doing #4b on the test yet ... (Click on the "moodle" tag below to find the instructions for logging in if you have forgotten.)

Homework and Exam 1 are both worth the same amount in the end, so your overall grade is an average of the two. In the end, I will drop your lowest homework, but I have not done this yet.

Please check to make sure everything seems to be in order. Wednesday, I'll have to upload midterm grades at some point.

Also, not doing the homework is really, really hurting some of you.

* If the in-class quiz did not help your exam grade, it counted toward your overall homework grade. This is not yet reflected in Moodle ... but your mid-term grade will reflect it, and I will try to post those revised numbers soon. This affects only about 20% of you.

## Tuesday, March 2, 2010

### Book contest

FYI:
The 4th Annual University Libraries Book Collecting Contest is underway.  The contest is for both undergraduate and graduate students.  Full information about the contest is on the UA Libraries Web site. http://guides.lib.ua.edu/BookCollectingContest

## Monday, March 1, 2010

### Homework 6 & 7

Homework sets 6 and 7 are combined, and due just as spring break begins. (Don't delay ...)

There are only 9 problems in this set, but they are a bit more involved, hence its counting twice as much.

We will go over the problems in quite a bit of detail in the classes leading up to the break.

UPDATE: re-posted with a few typos fixed and some useful integrals included. Same link above.

UPDATE: useful, also useful.