  We have identified seven independent pulsation modes in the helium-atmosphere
variable (DBV) white dwarf star CBS 114, based on 65 hours of time-resolved CCD
photometry from the 0.75-m telescope at SAAO. We interpret these pulsations as
non-radial g-modes with the same spherical degree l=1, as suggested by the mean
period spacing of 37.1+/-0.7 seconds. We use a genetic-algorithm-based fitting
method to find the globally optimal model parameters, including the stellar
mass (M_* = 0.73 M_sun), the effective temperature (T_eff = 21,000 K), the mass
of the atmospheric helium layer (log[M_He/M_*] = -6.66), and the central oxygen
mass fraction (X_O = 0.61). The latter value implies a rate for the
^12C(alpha,gamma)^16O reaction near S_300 = 180 keV b, consistent with
laboratory measurements.
