Resolution and Probability

A typical effect that occurs when changing the resolution of an RDF is a shift in peak intensity distribution. The higher the coincidence of a real distance with the calculated point, the more precise is the representation of the relative frequency of the distance. For example, an RDF descriptor with a resolution of 0.2 A represents a real distance of 1.51 A with two points at 1.4 and 1.6 A, both lying on the tails of the theoretical peak. The RDF does not appropriately represent the peak maximum at 1.51 A. 

Consequently, the frequency of the corresponding distance is lower than in a descriptor calculated with a resolution of 0.1 A, which would contain a peak at 1.5 A. This kind of inappropriate representation of individual frequencies occurs throughout the entire descriptor, and the effect on the accuracy of the descriptor is unpredictable. 

Consequently, the resolution of the distance dimension affects the accuracy of the probability dimension leading to the following effects  

---

The NMR spectrum exhibits resonances of particular polymers that possess stereosequence sensitivity. In the case of PLA, NMR spectra can distinguish the diads —LD— (or —DL—) and —LL— (or —DD—). But, the similar diads, —DD— and —LL—, or —LD— and —DL—, do not show different chemical shifts. In the stereosequence of PLA, the —DD— and —LL— produce an isotactic pairwise relationship, while —LD— and —DL— have the structure in a syndiotactic pairwise relationship. The observations from NMR have shown difficulties, such as overlaying of chemical shifts, insufficient resolution and probability of stereosequence formation due to polymer chains remaining in a huge macromolecule. For instance, for the stereosequence sensitivity of length n, there are possible combinations of pairwise... 

---