# PropagationSpectrumTransform

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#### PropagationSpectrumTransform

Section Utilities::oct-propagation_spectrum
Type integer
Default sine

Decides which transform to perform, if SpectrumMethod = fourier.

Options:

• sine:
Sine transform: $\int dt \sin(wt) f(t)$. Produces the imaginary part of the polarizability.
• cosine:
Cosine transform: $\int dt \cos(wt) f(t)$. Produces the real part of the polarizability.
• laplace:
Real exponential transform: $\int dt e^{-wt} f(t)$. Produces the real part of the polarizability at imaginary frequencies, e.g. for Van der Waals $C_6$ coefficients. This is the only allowed choice for complex scaling.

Source information

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