Bathochromic shift

Bathochromic shift (from Greek βαθύς bathys, 'deep'; and χρῶμα chrōma, 'color'; hence less common alternate spelling 'bathychromic') is a change of spectral band position in the absorption, reflectance, transmittance, or emission spectrum of a molecule to a longer wavelength (lower frequency). Because the red color in the visible spectrum has a longer wavelength than most other colors, the effect is also commonly called a red shift. Bathochromic shift (from Greek βαθύς bathys, 'deep'; and χρῶμα chrōma, 'color'; hence less common alternate spelling 'bathychromic') is a change of spectral band position in the absorption, reflectance, transmittance, or emission spectrum of a molecule to a longer wavelength (lower frequency). Because the red color in the visible spectrum has a longer wavelength than most other colors, the effect is also commonly called a red shift. Hypsochromic shift is a change to shorter wavelength (higher frequency) It can occur because of a change in environmental conditions: for example, a change in solvent polarity will result in solvatochromism. A series of structurally-related molecules in a substitution series can also show a bathochromic shift. Bathochromic shift is a phenomenon seen in molecular spectra, not atomic spectra; it is thus more common to speak of the movement of the peaks in the spectrum rather than lines. Bathochromic shift is typically demonstrated using a spectrophotometer, colorimeter, or spectroradiometer.