| Abstract: | The far infrared spectra of poly(L -proline) I (190–35 cm?1) and II (400–35 cm?1) were obtained in the solid state at both 300° and 110°K. A significant difference in the region below 100 cm?1 was observed. A very intense band located at 60 cm?1 in the infrared spectrum of form II has no counterpart in form I. This indicates the sensitivity of low-frequency vibrations to the difference in conformation assumed by both forms in the solid state. Additional bands observed in this study are correlated with ir and Raman data previously reported and tentative assignments are made using the results of normal mode calculations (in the single-chain approximation) which have been reported. |
