We present the microcanonical rates obtained in this way from instanton theory in Fig. . It can readily be seen that they are in very good quantitative agreement with the experimental results, which eluded previous studies based on Franck-Condon overlaps and onedimensional tunneling corrections. In particular, we contrast our results with those of Lykhin and Varganov, who employed the WC and Zhu-Nakamura formulas, as shown in the figure.