Magnetic Circular Dichroism - Theory

Theory

Consider a system are of localized, non-interacting absorbing centers. Based on the semi-classical radiation absorption theory within the electric dipole approximation, the electric vector of the circularly polarized waves propagates in the +z direction, where + and -denote to RCP light and LCP light respectively. In this system, ω = 2nν is the circular frequency, and Ii = n – ik is the complex refractive index. As the light travels, the attenuation of the beam is expressed as

I(z) = I0exp(−2ωkz/c)

where k is the absorption coefficient of the medium in the z direction. Circular dichroism (CD) is then defined as Δk = k – k+, and it follows the sign convention of natural optical activity. In the presence of the static, uniform external magnetic field, the Hamiltonian for the absorbing center takes the form Ĥ = Ĥ0 + Ĥ1 which is parallel to the direction of the propagation of the electric field k. Because the transition occur between the two eigenstates of Ĥ0, a and j, the absorption and the CD intensity are determined as follows:

Read more about this topic:  Magnetic Circular Dichroism

Famous quotes containing the word theory:

    Lucretius
    Sings his great theory of natural origins and of wise conduct; Plato
    smiling carves dreams, bright cells
    Of incorruptible wax to hive the Greek honey.
    Robinson Jeffers (1887–1962)

    The theory of the Communists may be summed up in the single sentence: Abolition of private property.
    Karl Marx (1818–1883)

    There never comes a point where a theory can be said to be true. The most that one can claim for any theory is that it has shared the successes of all its rivals and that it has passed at least one test which they have failed.
    —A.J. (Alfred Jules)