text: The alpha and beta Kamlet-Taft parameters quantify the extent of this effect.
full_question: The alpha and beta Kamlet-Taft parameters quantify the extent of this effect. This phenomenon is modeled as a double-well potential between donors and acceptors. SN1 reactions, but not SN2, are sped up by solvents demonstrating this effect. It is often incorrectly given as the reason for the higher melting temperatures of CG-rich DNA sequences. This interaction occurs perpendicular to the chains of antiparallel (*) beta sheets and links the amide groups of every fourth residue of an alpha helix. Alcohols have higher boiling points than ethers because of this phenomenon. This strong class of dipole-dipole forces classically requires nitrogen, oxygen, or fluorine to be present. For 10 points, name this intermolecular attractive force involving the lightest element.
first_sentence: The alpha and beta Kamlet-Taft parameters quantify the extent of this effect.
raw_answer: hydrogen bonding [or H bonding]