Search results
Results from the WOW.Com Content Network
Optical rotation, also known as polarization rotation or circular birefringence, is the rotation of the orientation of the plane of polarization about the optical axis of linearly polarized light as it travels through certain materials. Circular birefringence and circular dichroism are the manifestations of optical activity.
Specific rotation is an intensive property, distinguishing it from the more general phenomenon of optical rotation. As such, the observed rotation (α) of a sample of a compound can be used to quantify the enantiomeric excess of that compound, provided that the specific rotation ([α]) for the enantiopure compound is known.
In all materials the rotation varies with wavelength. The variation is caused by two quite different phenomena. The first accounts in most cases for the majority of the variation in rotation and should not strictly be termed rotatory dispersion. It depends on the fact that optical activity is actually circular birefringence.
The specific rotation [] is a physical property and defined as the optical rotation α at a path length l of 1 dm, a concentration c of 10 g/L, a temperature T (usually 20 °C) and a light wavelength λ (usually sodium D line at 589.3 nm): [4]
A simple polarimeter to measure this rotation consists of a long tube with flat glass ends, into which the sample is placed. At each end of the tube is a Nicol prism or other polarizer. Light is shone through the tube, and the prism at the other end, attached to an eye-piece, is rotated to arrive at the region of complete brightness or that of ...
For rotation from the laboratory frame to the local frame, the sign of the sine terms inverts. Linear polarizer (horizontal transmission) The Mueller matrices for other polarizer rotation angles can be generated by reference frame rotation.
See today's average mortgage rates for a 30-year fixed mortgage, 15-year fixed, jumbo loans, refinance rates and more — including up-to-date rate news.
Four weeks before he presented his completed theory of total internal reflection and the rhomb, Fresnel submitted a memoir [30] in which he introduced the needed terms linear polarization, circular polarization, and elliptical polarization, [31] and in which he explained optical rotation as a species of birefringence: linearly-polarized light ...