  Considerable interest is now focused on the detection of terrestrial mass
planets around M dwarfs, and radial velocity surveys with high-resolution
spectrographs in the near infrared are expected to be able to discover such
planets. We explore the possibility of using commercially available molecular
absorption gas cells as a wavelength reference standard for high-resolution
fiber-fed spectrographs in the near-infrared. We consider the relative merits
and disadvantages of using such cells compared to Thorium-Argon emission lamps
and conclude that in the astronomical H band they are a viable method of
simultaneous calibration, yielding an acceptable wavelength calibration error
for most applications. Four well-characterized and commercially available
standard gas cells of HCN, 12C$_2$H$_2$, 12CO, and 13CO can together span over
120nm of the H band, making them suitable for use in astronomical
spectrographs. The use of isotopologues of these molecules can increase line
densities and wavelength coverage, extending their application to different
wavelength regions.
