Conformational notation dihedral angles

Standard notation will be used to describe the conformations defined by the values of dihedral angles O about successive C-C bonds in chains of polymers and model molecules containing a backbone of tetravalent... 

A gauche conformation with a positive dihedral angle of -f- 60° can be denoted g, while a gauche conformation with a dihedral angle of -60° (i.e., -I- 300°) can be denoted g. The anti conformer can be denoted a. The anti conformer may also be denoted t, because the 180° dihedral angle conformation is often called "trans" in the physical chemistry literature. Organic chemists usually reserve the term trans for cis, trans isomers, however. This compact notation is particularly useful for representing several consecutive conformations in concise fashion. For example, three conformations of... 

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