To whom it may concern,
From ccpnmr, I have got the 3JHNHA coupling calculated from Icross/Idia of HNHA spetrum. However, when I calculated manually with the formula of Icross/Idia = tan2(JHNHA*2*3.14*0.01305), the resultant value of JHNHA doesn't match that delivered by ccpnmr. Actually, the ratio of JHNHA calculated manually to JHNHA calculated by ccpnmr is constantly 0.900***.
Can you please tell me how ccpnmr derived the JHNHA from HNHA spectrum?
Cheers,
Sidney
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