It is found that the 750 cm–1 band in pure tertiary butyl alcohol shows attributes of a complex structure that can be interpreted as a result of the superposition of several closely located lines belonging to different aggregates of alcoholmolecules. As the alcohol is diluted with neutral solvents, the width of this band passes through a maximum that corresponds to the concentration of the mixture with comparable contents of various most stable aggregates in the solution. The performed quantum-chemical calculations confirm the complexity of the 750-cm–1 band of pure alcohol caused by the aggregation of molecules by means of hydrogen bonds. The calculated energy gain due to the formation of a hydrogen bond (dimer) amounts to 19.7 kJ/mole, and the length of the hydrogen bridge equals 2.068 Å.