Poly(L‐alanine): Investigation of alpha‐helix and betal‐sheet forms by low‐temperature specific heat measurements (1.5–20°K)

For an ideal one‐dimensional solid, the low‐temperature specific heat, C , is proportional to temperature T 1 , for an ideal two‐dimensional solid C is proportional to T 2 . We have observed such one‐ and two‐dimensional behavior in alpha‐ and beta‐poly( L ‐alanine) in the temperature range 1.5–20°K (also intermixed with a three‐dimensional behavior). A specific heat anomaly has also been observed. These measurements are important in evaluating the effective elastic constants, including hydrogen bonding, of the biopolymers. They also provide essential information for vibrational theories of poly( L ‐alanine), which up until now have been based on high‐energy data.