 CH2+ p.d. cf. Theodorakopoulos & Petsalakis '91; maximum rate
    7
    1  1710.0  0.210E-15
    2  1340.0  0.110E-17
    3  1188.0  0.130E-15
    4   968.0  0.500E-15
    5   944.0  0.240E-15
    6   925.0  0.380E-15
    7   916.0  0.150E-15
    0
