Molecular Gas and Star-Formation In Low Surface Brightness Galaxies
  We have obtained CO(J=2-1) spectra of nine face-on low surface brightness
galaxies(LSBGs) using the JCMT 15-meter telescope and observed Ha images using
the 2.16-meter telescope of NAOC. As no CO has been detected, only upper limits
on the H2 masses are given. The upper limits of total molecular hydrogen masses
are about (1.2-82.4) x 10^7 Msun. Their star formation rates are mainly lower
than 0.4 Msun/yr and star formation efficiencies are lower than 1.364 x 10^10
/yr. Our results show that the absence of molecular gas content is the direct
reason for the low star formation rate. The low star formation efficiency
probably resulted from the low efficiency of HI gas transforming to H2 gas.
