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''.

Hypsochromic shift is a change to shorter wavelength (higher frequency).

Conditions

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.

:$\Delta\lambda = \lambda^_ - \lambda^_$ where $\lambda$ is the wavelength of the spectral peak of interest and $\lambda^_ > \lambda^_$

Detection

Bathochromic shift is typically demonstrated using a spectrophotometer, colorimeter, or spectroradiometer.

See also

*Chromism
*Solvatochromism
*Spectroscopy

References

{{Reflist

Chromism
Spectroscopy