For the lower alcohols, the tendency to serve as hydrogen bond donors (HBD) toward solutes is commonly expressed through various semiempirical scales incorporating polarity and acidity parameters. In this report a simplified model for such HBD acidity is proposed which is based upon molecular orbital perturbation theory. Two first-order perturbation terms are included in the Hamiltonian which carry over to the total energy function for the highest occupied molecular orbital (HOMO) of the alkanol. Quantitative tests using dipolarity and HBD acidity data support the two-term formulation of the Hamiltonian. The alkanols, water, and the alkyl amides are among the most familiar examples of hydrogen bonded liquids. Their abnormal values for several bulk solvent properties lead to their placement in a completely separate solvent class within the Chastrette-Purcell (Chastrette et al., 1985) general scheme for solvent classification, namely, the hydrogen bonding strongly associated category (HBSA). Although the bond enthalpy for a single hydrogen bond may amount to no more than ten to fifteen percent of that for a normal covalent bond, the presence of several hydrogen bond donor sites within polyfunctional molecules can have important consequences. This effect is well illustrated by hydrogen bond donor-acceptor stabilization of specific stereo conformations in DNA, proteins and other nanostructures among biomolecules, as well as in related and generalized molecular selfassembly reactions. The thermodynamics for the latter processes have been analyzed recently in a review by Whitesides et al. (1991). For any simple hydrogen bond donor (HBD)-to-hydrogen bond acceptor (HBA) reaction represented by equation 1, the fundamental determinants for the kinetics of the net process will be the Gibbs free energy and entropy factors assignable to the respective reactants and the activated state.