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ML_LMAX2 = [integer]
|Default: ML_LMAX2||= 4||for ML_LAFILT2 = .TRUE.|
Description: This tag specifies the maximum angular momentum quantum number of spherical harmonics used to expand atomic distributions within the machine learning force field method.
To construct an atomic environment descriptor the atomic probability density
where is an approximation of the delta function, is expanded in terms of radial basis functions and spherical harmonics (see this section for more details):
The tag ML_LMAX2 specifies the maximum angular momentum quantum number of spherical harmonics used in this expansion.
|Mind: This tag is only relevant for the angular descriptor . The corresponding number of expansion coefficients scales linearly with and is also depending on ML_MRB2 and the number of elements present.|
By default an angular filtering (see ML_LAFILT2 and ML_IAFILT2) with a filtering parameter of ML_AFILT2=0.002 is used where a value of ML_LMAX2=4 is perfectly safe for most applications. If the angular filter is switched off we recommend to use a value of ML_LMAX2=6 (this is then the default value).