Hi everyone, I wanted to know if any of you knows very good sources for quantum mechanics and spectroscopy fundamentals, like greats books, youtube videos (lectures), or any other option. I' m studying spectroscopy at the moment, and last year I've done the Physical Chemistry II course ( quantum part), but I'm really heavily struggling with understanding and remembering things... I've absorbed a few concepts, but it seems like after a few months I forget lots of notions, and when I go back revising them, it's like doing them kinda all over again, and that makes the study of spectroscopy even harder. I'd like to hear if any of you succeeded understanding deeply this field, and how did you do it. Any advice is really appreciated P.s. I've seen tons of material and books for both courses, but I didn't find anyone of them explaining things in an efficient way to me, they're always taking some things for granted.