Figure also shows that the shapes of the lines include information about possible long-range J-couplings between A and C. Such line shape information can be highly diagnostic by indicating that long-range couplings exist, compared to situations where lines are narrow, even though the values for these coupling constants correlate with the respective line width. However, by taking these QM relations into account, overlapping signals such as those shown here can still be completely resolved and all related chemical shifts and relevant coupling constants can be determined. Moreover, QM-based analysis can provide the accurate molar ratio of two spin systems, which is hardly accessible via integration, and still difficult and/or less accurate when applying peak-fitting methods (PF-qNMR) because there are more lines than peaks to be fitted.