Amazing professor. I'm not a hard worker and don't like going to class, but this class was absolutely an exception. He had office hours all the time, and I'd attend almost all of them. He'd buy snacks for us and was so helpful during them.

You can tell he's passionate too. He was nearly in tears as he derived Schrodinger's equation and observed its beauty. Inspiring. Every day he lectures with such a fire and passion for quantum mechanics that he's sweating from head to toe. Made me work harder just watching him teach.

He buys you Subway during exams too. When I did well in the class, he sent me an email congratulating me, and promising to write a heartfelt recommendation letter should I ever need one. What an amazing human being.

Took this class in 2017 Summer Session A. Amazing professor and amazing person. He deeply cares about his students and performs well above and beyond his duties as a professor. His explanations are clear, but they tend to be mildly obscured by his accent. He has a high expectation of his students, which he tells to all his students before the class begins, so effort is required to do well in his class. He has a 1-2 question daily preview due every day and a 3-5 question self evaluation due every Friday. Before every major test, if so requested, he will make a practice self evaluation that is 10 questions long. Though only 2 questions are due, I highly recommend completing all of the questions, since they are all relevant to the test. Overall, he's a great professor and I'm lucky to have him as one of my firsts.

Edit (6/7/2018): Professor Lin was one of my first professors. Now that I've had other professors as a comparison, I believe that the praise I gave to him is severely lacking to what he deserves. Quite honestly, Professor Lin performs well above and beyond other professors that I've rated 5/5 on Bruinwalk, so he should really be getting something like a 6 or a 7 on the same scale. I cannot stress how fantastic of a professor Lin is. I would highly encourage you to take a course with him if possible.

Tough class, but greatly outweighed by the helpfulness of the professor. He provides office hours and explains in great detail the topics you are confused about. He is very responsive in his emails. Amazing professor who will go out of his way to make sure his students succeed in the class. 10/10

I am a student from China. I enrolled in this course to be qualified for the F1 visa, in order to do travel study in US this summer. Mr. Lin makes chemistry so interesting and exciting. I enjoyed very much his teaching style: clear, logical, rigorous, and humorous. He seemlessly connects his lectures, problem sets, and self evaluations to modern research publications. In fact, I am so proud of myself that I can predict in the final exam the HOMO-LUMO transition of a dream molecule "cyclic polyyne C10" and prove that quantum tunneling of 2H in palladium electrode by itself cannot trigger cold fusion. Going to his "quantum paradise" (class meetings and office hours) becomes the priority and focus of my everyday activities. Mr. Lin is very kind and generous. Since the office hour 12-1 follows the class meetings immediately and is popular, he frequently brings some snack to the office hours, so that we will not get too hungry. Since the review sessions are 4-7pm (in fact, it ended at 8pm) the two nights before the final and all class went, he treated the class pizza and snapple during the break, so that we will not get too hungry. I hope to become a professor in the future and he is my role model. Perhaps I will use his chemistry jokes in my teaching, too. They are so funny :) The only complaint I have is: since this course is so overwhelming and there is always homework due in every class meeting, I could not do any travelling over the past six weeks :( I may come back next summer to take his course again.

We just finsihed the final exam this morning. I am an EE major. I took this course merely to fulfill my course requirements so that I can graduate. But after six weeks, I am thinking about the possibility of pursuing quantum mechanics in the future. Prof. Lin is a very kind, caring, and passionate professor, with a good sense of humor. He integrates modern chemistry research such as quantum teleportation, quantum eraser, quantum imaging, quantum computing, quantum corrals, molecular cascades into the lectures, homework, and exams. This is the best course that I have taken so far at UCLA. But be warned, Prof. Lin imposes high standards and has high expectations towards his students (and even higher standards towards himself). Five homework due per week: 4 daily previews and 1 problem set. It will take you an enormous amount of time to study, think, and do homework. But you will learn A LOT! Very strongly recommended. Take his courses whenever possible.

I was in Prof. Lin's Chem 14A Summer C 2016. I have learned a lot from this class and am fortunate to have Prof. Lin as my first college professor. He taught me so much, not only chemistry, but also about how to work hard and smart through true understanding, how to bring myself up, being an academic family, the importance of attitude and kindness. I am seriously thinking about changing my major from pre-med to chemistry. But be warned: his expectation is very high and workload very heavy (daily previews or weekly problem sets due in each and every lecture and TA discussion).

I took the class as an international high school student, and since I've got an A+, there's nothing you should worry about.

PRO:
-- The lecture is largely clear. Occasionally some contents aren't explained with clarity, but with a little bit of research you can figure it out yourself, and I don't assume any professors can make everything in his/her class clear.
-- The professor is VERY considerate and cares DEEPLY about his students. Let me just say this, you're unlikely to encounter another professor that cares this much, especially for an introductory course. Prof. Lin is very responsible and carefully reviews every piece of homework that we submitted. The grading is fast. He remembers every student's name. He replies his email generally within an hour (it's like he never sleeps). And yeah, those rumors are true, he does provide awesome Asian snacks, pizzas and Subways during tests and review sessions.
-- The course content is very challenging at the start, especially with the Schrodinger equation part. But if you fully grasp the essence of wavefunctions, then the rest of the course is just a breeze. Of course, even though the course only has Math 31A as its requisite, you need to know your stuff about integrals and Taylor expansions. A little bit of knowledge of differential equation would help, but not much.
-- Even though the content is harder than usual, it's not very likely that you'll get a grade below A-, seriously. Prof. Lin goes through the contents for so many times we can even remember his tones when delivering the derivations. Plus, he presents practice tests, which are very similar to the real ones.
CON:
-- He carries a somewhat obscure accent, similar to Chinese accent but not quite. Anyway the first few lectures would be miserable, just because of his accent. But you'll quickly catch on.
-- Because Prof. Lin repeats the contents for so many times since he wants to make sure everybody understands what's going on, he usually lags quite a bit. By the time the course ends, there're still around 25 percent of materials that weren't lectured at all. This can be frustrating, but the good part is you won't feel confused at all about what you've been lectured on.
-- Workload is relatively heavy. There're previews due every day from Monday to Thursday, each one featuring one to two questions; usually the contents are way ahead of what's being taught in the lecture so you really need to read your textbook. The questions are not hard, though. There's a problem set that reviews lecture contents with around 4 questions that's due every Friday. The problem set is even easier except for the last one, which is very math-heavy.
-- Attendance is mandatory, but I haven't adapted to college culture of skipping classes yet, so this isn't much of a problem. Also, you can skip at most 2 lectures or discussions.

RECOMMENDATION POLICY: I have never seen a professor that OFFERS you recommendations, but that's what he did. Basically every lectures he talks about how you need to work hard, and if you get satisfactory grades, he'll personally write you a very LONG recommendation letter, one that's optimized based on each student. So if you want a recommendation that's actually ABOUT you and is actually useful, go to his class.

GRADING POLICY: One midterm and one final, each for three hours. The higher one constitutes 32 percent while the low one constitutes 29 percent. There's 18 percent for previews and another 18 percent for problems sets, so do your homework. The rest of the points are assigned by TA based on your "participation" in discussions. There're 2 bonus points if you attend all the classes (those 2 occasions don't count) and pend all homework on time. You need 98 percent for A+ and 92 percent for A.

I'm still exploring school options but Prof. Lin literally deepens my appreciation of UCLA. He's a very hard-working professor, so choose him whenever you can.

Professor Lin is the nicest professor I have ever had! He will go through the photo roster to memorize names and he WILL know who you are before you even introduce yourself. He also hands out import cookies to people who receive the highest test scores and provide mountains of pizza at review sessions. He also remembers you after the course and any details about yourself that you may have told him, so he's a good professor for future letters of rec.

His class is also an easy A as long as you can put in the time to go to numerous office hours to get the TAs to help do the problem set and practice exam questions for you because 90% would be impossible to do on your own. The good news is once you get the answers, review, and moderately understand them enough to recreate the answers on the exam you'll do fine on exams as they're basically the same questions.

So if you want a good self-esteem boost and a nice professor who occasionally gives you free food, Lin is the professor for your first quarter he's the professor for you! However, if you actually want to learn anything the other Chem 20A classes are learning, you may want to steer clear. Lin goes over mostly conceptual topics that you will encounter in future courses, but you'll have no understanding of while you are taking 20A.

I went to about half the lectures, understood less than half the lectures, but went to many office hours and got a friend to pickup lecture handouts for me and I ended up with an A. My little retention of high school chem was also enough to get me through future chem classes so not learning much in chem 20A wasn't a big issue. NO RAGRETS!

I got an a in the class but his accent is horrible and he doesn't teach the same material as the other chem 20a professors, but the class really is an easy a if you go to a few office hours. He assigns practice sets which are very difficult but often he will give huge hints and so will the TA's. Once you can do the problem set, the exams are very similar and some problems are exactly the same.

His lectures are super confusing and unhelpful, but he gives out the lecture slides. Also lecture is mandatory because you have to hand in a problem each day which sucks.

Selling the text book (Oxtoby 7/e) for 60$. I barely used it, but it is the paper back version/international version. Same thing just a different cover.
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Lin is very motivated to ensure the student's success. He is a very nice professor. While his accent is a little hard to understand, you'll quickly catch on and be able to follow along. That being said you do need to find a good t.a. that will help you with understanding the material. TA Zhao was a life saver. Quantum Chemistry was a beast and especially difficult this year as it was heavily influenced by derivations. His practice exams are very similar to the midterm and finals, so be sure to understand the material on there. While, the workload is very heavy, and basically takes away your social life, you learn a lot. He basically ensures your success with all the previews and practice self evaluations. All of the questions he assigns for homework are odd numbers so go to the library, get the solutions manual and check your work. I recommend this professor for preparing you for the heavy course load for chem 20b.