If you find a free PDF online, be cautious. Many such files contain malware, outdated answers (confusing 4th edition with 3rd or 5th), or incomplete problems.
Several academic repositories host portions or full versions of the solutions manual and the textbook itself: pavia spectroscopy 4th solution pdf
NMR, including chemical shifts, integration, and complex coupling patterns (multiplets). If you find a free PDF online, be cautious
Detailed breakdowns of fragmentation patterns and molecular ion identification. Infrared Spectroscopy (IR): including chemical shifts
The solutions here go beyond just calculating degrees of unsaturation. They explain why a given formula suggests an aromatic ring vs. a carbonyl plus a double bond. For example, a solution might show: C₄H₈O₂ has one degree of unsaturation. Possibilities: an ester, a carboxylic acid, or an aldehyde with an alcohol. IR is needed to distinguish.