Why the direction of IR peak and UV peak are opposite?

The direction of infrared (IR) and ultraviolet (UV) peaks in a spectrum is opposite due to the nature of their energy levels. IR peaks correspond to vibrational transitions in molecules, which occur at lower energy levels, while UV peaks are associated with electronic transitions, involving higher energy levels. As a result, IR peaks are typically found at longer wavelengths (lower energy) and UV peaks at shorter wavelengths (higher energy). This fundamental difference in the types of molecular transitions leads to their opposing directions in spectral representation.