Prof. Felker does teach pretty fast, and grades entirely without remorse or pity. However, I did enjoy the class, even in the remote quarter, because when we told him that the pre-recorded lecture and assigned textbook problems with no answer key and nothing else to help us study was not helping us learn the material, he made an effort to improve, and started holding in person office hours and going over some problems. I really enjoyed these sessions because in quantum it's really easy to get stuck on something stupid or some small concept that you've just missed, and having someone show you things is actually pretty nice. He also gave a pretty generous curve which was great lol. I think something that was nice about the recorded lectures is that you can put it on 1.5x speed to listen to him talk and then pause it to copy down the math when he's done explaining. I did end up doing some textbook problems, but definitely not all the ones he assigned.

I'm wondering if he is the same professor as the previous reviews described, or if he treated the online quarter with even the slightest seriousness.
In the first 2 or 3 weeks, he used written notes with contents that made some sense and easy to follow. But after that, he switched to typed notes, and basically reads off his handout in his pre-recorded lectures 90% of the time, which of course is faster than possible to follow. (I'm wondering if this can take the full lecture time, how he even manages to finish lectures during normal quarters.) He gives almost zero elaboration on why the derivation goes that way, and absolutely no annotation on the screen. To make things worse, his mic is unclear from time to time.
For practice questions, he gives questions numbers in books and never gave corresponding answers. The previous reviews about his exams are no longer true, as you will need to prove or calculate things that do not exist in the textbook (e.g. matrix element of Hamiltonian).
Please AVOID taking prof. Felker, if this online quarter is representative of how he teaches.

EDIT: after this class I took Chem 115A with Schwartz, a supposedly higher level of quantum mechanics. What Felker does in 113A is exactly the material in that class, except he makes zero preparation for the advanced concepts and his point articulated extremely poorly. DON'T TAKE THIS CLASS WITH HIM!

This class was okay. I wouldn't necessarily recommend it but I wouldn't tell people to avoid it either. Lectures were a little unclear, as they are mostly derivations that are hard to follow if you aren't very math-oriented. However, these complex derivations aren't needed for the exams.

Exams were mostly reasonable and focus on main ideas from the lectures and homework. He does not require that you evaluate difficult integrals, and both midterms and most of the final was in variables. The exams are open book and it's important that you know how to find things in your textbook. Sometimes he throws in concepts that were not really emphasized in the homework, but are pretty simple if you know where to find it in the book.

Overall, it's not a bad course as long as you keep up with the work and get help when you need it.

My love of Physical chemistry has simply initiated in Prof. Felker's quantum chemistry course. I admit that he may be a bit more difficult than other prof. coz he used too much math and derivations in the class. But,those made me UNDERSTAND every physical parameter with ALL possible relations to others. His course was full of derivations, integrations, and differential equation stuff. But, he allowed open-book, open-note exams which made student a bit more relaxing since NO need to memorize anything. The TRUE result about taking Prof. Felker's course made me interested into Physical chemistry with strong math background. He is actually a very good Pchem prof., shows the mathematics side of chemistry and makes students convince ALL formulas in chemistry simply came from derivations. Thanks a lot, Prof. Felker!