create a function to compute DOS from a one-phonon SQE

[yxqd]

Assume the SQE contains only one phonon scattering

The original method implemented by Max assumes that the SQE is in a rectangular area where all data is valid. And it adjusts the Q dependency of the intensities (Debye Waller factor) and then collapse the data along Q axis to obtain a S(E) that can be converted to DOS easily.

The limitation is that this approach has to discard a lot of data. Doug suggested that we should be able to use all the data if we carefully keep track of the multiplication factors and the boundaries of dynamic range.

The new algorithm here will overcome that limitation. We should be able to use the full dataset by masking the data outside the dynamical range.

[yxqd]

There are now two test cases

• Convert from a simulated one-phonon scattering SQE to DOS

SQE:

DOS:

• Convert from experimental IQE (not corrected for multiphonon SQE yet) to DOS

IQE:

DOS: