  The combined all-electron and two-step approach is applied to calculate the
molecular parameters which are required to interpret the ongoing experiment to
search for the effects of manifestation of the T,P-odd fundamental interactions
in the HfF$^+$ cation by Cornell/Ye group [Science 342, 1220 (2013); J. Mol.
Spectrosc. 300, 12 (2014)]. The effective electric field that is required to
interpret the experiment in terms of the electron electric dipole moment is
found to be 22.5 GV/cm. In Ref. [Phys. Rev. D 89, 056006 (2014)] it was shown
that another source of T,P-odd interaction, the scalar-pseudoscalar
nucleus-electron interaction with the dimensionless strength constant $k_{T,P}$
can dominate over the direct contribution from the electron EDM within the
standard model and some of its extensions. Therefore, for the comprehensive and
correct interpretation of the HfF$^+$ experiment one should also know the
molecular parameter $W_{T,P}$ the value of which is reported here to be 20.1
kHz.
