According to the Helsinki website, the infrared spectrum of isopentyl acetate contains one ester peak in the 1735–1745 cm -1 range, hydrocarbon bonds just below 3000 cm -1, and carboxyl and carbonyl C-O bonds between 1050 and 1300 cm -1. At least one of each exists.
According to Chemguide, each molecule that is chemically distinct will reflect infrared of different wavelengths than any other molecule. When plotted on a graph, the uniqueness of reflected wavelengths between one type of molecule and a completely different type of molecule forms a "fingerprint," which can be used to differentiate one chemical from another.
