  An electrostatic hexapole lens is used to manipulate the transverse
properties of a beam of barium fluoride molecules from a cryogenic buffer gas
source. The spatial distribution of the beam is measured by recording
state-selective laser-induced fluorescence on an emccd camera, providing
insight into the intensity and transverse position spread of the molecular
beam. Although the high mass and unfavorable Stark shift of barium fluoride
pose a considerable challenge, the number of molecules in the low-field seeking
component of the N=1 state that pass a 4 mm diameter aperture 712 mm behind the
source is increased by a factor of 12. Furthermore, it is demonstrated that the
molecular beam can be displaced by up to +/-5 mm by moving the hexapole lens.
Our measurements agree well with numerical trajectory simulations. We discuss
how electrostatic lenses may be used to increase the sensitivity of beam
experiments such as the search for the electric dipole moment of the electron.
