Chemical Physics Letters, Vol.506, No.4-6, 196-200, 2011
Conformational statistics of n-butane in the condensed phase and the effects of temperature
Experimental dipolar couplings are obtained from the H-1 NMR spectra of n-butane dissolved in a liquid crystal over an 80 degrees temperature range with Covariance Matrix Adaptation Evolutionary Strategies (CMAES). These observables are rationalized using a size-and-shape potential [E. E. Burnell, C. A. de Lange, Chem. Rev. 98 (1998) 2359], CI (2k), and with a modified chord model [D.J. Photinos, E. T. Samulski, H. Toriumi, J. Phys. Chem. 94 (1990) 4694], CCd, for the orientational ordering potential. The trans-gauche energy difference, E-tg, is temperature dependent when using the CCd model and temperature independent when using the CI (2k) model for the orientational ordering potential. (c) 2011 Elsevier B.V. All rights reserved.