  Present and future high-precision radial-velocity spectrometers dedicated to
the discovery of low-mass planets orbiting low-mass dwarfs need to focus on the
best selected stars to make an efficient use of telescope time. In the
framework of the preparation of the SPIRou Input Catalog, the CoolSnap program
aims at screening M dwarfs in the solar neighborhood against binarity, rapid
rotation, activity, ... To optimize the selection, the present paper describes
the methods used to compute effective temperature, metallicity, projected
rotation velocity of a large sample of 440 M dwarfs observed in the visible
with the high-resolution spectro-polarimeter ESPaDOnS at CFHT. It also
summarizes known and newly-discovered spectroscopic binaries, and stars known
to belong to visual multiple systems. A calibration of the projected rotation
velocity versus measured line widths for M dwarfs observed by the ESPaDOnS
spectro-polarimeter is derived, and the resulting values are compared to
equatorial rotation velocities deduced from rotation periods and radii. A
comparison of the derived effective temperatures and metallicities with
literature values is also conducted. Finally, the radial velocity uncertainty
of each star in the sample is estimated, to narrow down the selection of stars
to be included into the SPIRou Input Catalogue (SPIC).
