Stolze, JoachimBrandt, Uwe2008-06-032008-06-031983-10-20Brandt, Uwe; Stolze, Joachim: Thermodynamics of the molecular polaron : the transition to self-trapping. In: Journal of Physics C Nr. 29, Jg. 16(1983), S. 5617-5627, doi: 10.1088/0022-3719/16/29/015.http://hdl.handle.net/2003/2541710.17877/DE290R-3353The thermodynamics of the molecular polaron model-a two-level system coupled to a harmonic oscillator-is studied. Close upper and lower bounds to the free energy are derived by means of Tchebycheff-Markov inequalities and are compared with the results of other authors. The 'nearly free' behaviour for high temperatures is confirmed. The self-trapping effects at low temperatures are weaker than predicted earlier. In contrast to the prediction of mean-field theory, the transition between the two temperature regimes is not a sharp phase transition but rather a smooth crossover.enThe Institute of Physics51010.1088/0022-3719/16/29/015article (journal)