Fractional area-weighted surface charge of hydrogen bonding donor atoms FHDCA2

Definition:

HDCA2 -  area-weighted surface charge on hydrogen bonding donor atoms, selected by threshold charge

TMSA - total molecular surface area

Reference:

1. D.T. Stanton, P.C. Jurs, Anal. Chem., 1990, 62, 2323; D.T. Stanton, L.M. Egolf, P.C. Jurs, M.G. Hicks, J. Chem. Inf. Comput. Sci., 1992, 32, 306.