In spectroscopy, hypsochromic shift (from Ancient Greek ὕψος (upsos) 'height' and χρῶμα (chrōma) 'color') is a change of spectral band position in the absorption, reflectance, transmittance, or emission spectrum of a molecule to a shorter wavelength (higher frequency).
[1] It should not be confused with a bathochromic shift, which is the opposite process – the molecule's spectra are changed to a longer wavelength (lower frequency).
Hypsochromic shifts can occur because of a change in environmental conditions.
For example, β-acylpyrrole will show a hypsochromic shift of 30-40 nm in comparison with α-acylpyrroles.
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