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# ML FF SION2 MB

ML_FF_SION2_MB = [real]
Default: ML_FF_SION2_MB = 1.5*ML_FF_SION1_MB

Description: This tag specifies the width of the Gaussian functions used for broadening the atomic distributions of the angular descriptor within the machine learning force field method.

The unit of ML_FF_SION2_MB is in ${\displaystyle \AA }$. Test calculations showed that a 1.5 smaller value for the broadening of the radial descriptor compared to the angular descriptor (see ML_FF_SION2_MB) gives optimal results. This tag is not used if ML_FF_IBROAD1_MB=1 (which is not the default).