Time-independent and time-dependent perturbation theory, including the WKB approximation.
While often referred to as "Bransden Joachain Quantum Mechanics," the correct title for the comprehensive textbook usually associated with these authors is Physics of Atoms and Molecules . They also have a smaller, introductory book titled Quantum Mechanics (often in a two-volume set), so ensure you are looking for solutions matching the specific book you are using. Time-independent and time-dependent perturbation theory
If stuck, look at only the first two lines of the solution to find the "starting point." Time-independent and time-dependent perturbation theory
Quantum mechanics requires a specific type of mental endurance—the ability to sit with a difficult problem and try multiple approaches. Immediate access to solutions erodes this resilience, which is a critical skill for a research physicist. Time-independent and time-dependent perturbation theory