Unlike the historical approach (starting with the photoelectric effect and Bohr’s model) used by Eisberg and Resnick, or the "shut up and calculate" approach of Griffiths, Ohanian adopts a approach.
While many academic file-sharing sites (like Library Genesis or Sci-Hub) contain older editions of textbooks, the copyright status of Ohanian’s book is somewhat complex. The original edition was published by (now part of Pearson). Later, Norton published a reprint edition. Because the book is older (published in the late 1980s/early 1990s), it is out of print in many regions, but not strictly in the public domain.
If you still wish to locate a PDF legally:
Hans C. Ohanian is a renowned physicist and author known for his ability to demystify complex subjects. His textbooks on gravitation, classical mechanics, and physics for engineers are praised for their pedagogical clarity. In Principles of Quantum Mechanics , Ohanian brings this same lucidity to the often-counterintuitive realm of subatomic particles. Core Features of the Book
3D Particles, Angular Momentum, Central Potentials, and Spin/Exclusion Principle.
