Hypsochromic Shift
Get Hypsochromic Shift essential facts below. View Videos or join the Hypsochromic Shift discussion. Add Hypsochromic Shift to your PopFlock.com topic list for future reference or share this resource on social media.
Hypsochromic Shift

Hypsochromic shift (from ancient Greek ? (upsos) "height"; and chr?ma, "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). Because the blue color in the visible spectrum has a shorter wavelength than most other colors, this effect is also commonly called a blue shift.

This 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 hypsochromic shift. Hypsochromic 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.

${\displaystyle \Delta \lambda =\lambda _{\mathrm {observed} }^{\mathrm {state1} }-\lambda _{\mathrm {observed} }^{\mathrm {state2} }}$ where ${\displaystyle \lambda }$ is the wavelength of the spectral peak of interest and ${\displaystyle \lambda _{\mathrm {observed} }^{\mathrm {state1} }>\lambda _{\mathrm {observed} }^{\mathrm {state2} }}$

For example, ?-acylpyrrole will show a hypsochromic shift of 30-40 nm in comparison with ?-acylpyrroles.