The rate constant for the ion-symmetrical top quadrupole capture is es
timated using a classical variant of the microcanonical version of the
transition state theory. The symmetrical top quadrupole reacts faster
at all energies than the corresponding linear quadrupole. The depende
nce of the capture rate on the dimensionless energy parameter B-3, whi
ch determines the effect of energy on the capture rate, deviates much
from linearity even at the lowest energies. Another dimensionless para
meter, the molecular parameter zeta, determines the contributions of t
he orbital and rotational components to the total rotational momentum
of the system. The temperature dependence of the capture rate constant
is estimated for both the extreme regions of zeta: the region of orbi
tal momentum preponderance and the region of rotational momentum prepo
nderance. In the first region the capture rate for the symmetrical top
quadrupole is slightly faster than for the linear quadrupole. This di
fference practically vanishes in the second region.