For the RISC of S 1 -T 1 crossings, increasing temperature evidently facilitates the corresponding rates. For example, as shown in Table , the calculated RISC rate at FC approximation increases from 1.9 × 10 4 to 3.1 × 10 5 s -1 . The HT contribution to the RISC rate is also one-order of magnitude larger than FC in room temperature. However, as the temperature increases, the difference between FC and HT contributions decreases.