We expect that a more in-depth analysis and parameter fine-tuning could lead to even better agreement with theory and experiments. We performed the first systematic calculation of puckering free energy landscapes for the series of α and β -aldohexoses using the latest parameter set (45a4) for the gromos force field. While the realism in reproducing the population of inverted chairs and boats for β -d- glucose has surely improved with respect to the 45a3 set, it is still in marked quan- titative disagreement (around 10 kJ/mol) with available theoretical models. Besides that, we discovered that the free energy difference between inverted chairs and chairs of other pyranoses modeled using the 45a4 set leaves still much to be desired: galactose, mannose, allose, and α -d- Glc present a sizable population of the inverted chair conformer, which has never been observed experimentally. On the contrary, the population of the inverted chair conformer of idose resulted to be negligible in simulation, whereas theoretical approaches VI. CONCLUSIONS 22 and Tab. V. In Fig. 7 the free energy differences between inverted chair and chair conformers are compared again with the theoretical predictions of Ref. 63 and Ref. 62. The improvement with respect to the results obtained with the 45a4 set (Fig. 5) is striking. Both the α and β series reproduce now the qualitative trend of the theoretical estimates. Galactose, mannose, and talose are not anymore below the 2 k b T threshold, and the value of gulose, altrose and idose free energies diminished considerably. Also the gap between the α and β anomers is now reproduced reasonably well, being on average ≃ 5kJ/mol. Noticeably, the height of the free energy barrier of β -d- Glc has been increased considerably, from ≃ 25kJ/mol to ≃ 45kJ/mol. This increase, which changes dramatically the kinetics of the conformational transition of β - d- Glc, has no counterpart in any other β − anomer. The situation for α − anomers is slightly different, because the height of the free energy barrier close to $^{4}$C$_{1}$ increased markedly for α -d- Tal and α -d- Gul and, at the same time, decreased for α -d- All and α -d- Alt. Unfortunately, the population of inverted chairs in α -d- Ido is still lower than that of chairs, whereas both theory and experiment show a preference for the $^{1}$C$_{4}$ conformer. How- ever, given the fact that these changes are not sugar-specific, the result obtained is to our opinion still remarkable, as the ability to reproduce puckering properties has increased dra- matically, with respect to the 45a4 set.