High frequency vibrational modes of poly(dA) · poly(dT) and poly(dAT) · poly(dAT)

The Raman and infrared spectra of poly(dA) · poly(dT) and poly(dAT) · poly(dAT) have been recorded. Normal coordinate analyses have been performed for these two polymers to obtain the fundamental modes. We use a valence force field deduced from literature values and from a refinement of a diethyl phosphate potential. Non-bonded interactions are not included. Extensive descriptions of each mode are given allowing qualitative understanding of some of the spectral difference found between the two polymers.