J. Phys. Chem. 1996, 100, 20173-20174
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ADDITIONS AND CORRECTIONS 1996, Volume 100 S. L. Wallen, B. J. Palmer, B. C. Garrett, and C. R. Yonker*: Density and Temperature Effects on the Hydrogen Bond Structure of Liquid Methanol Page 3959. A computer error was discovered in the routine used to calculate the hydrogen-bonded cluster distributions from the molecular dynamics simulations. Although the error does not affect our conclusions, there is a noticeable change in the corrected hydrogen bond cluster distributions calculated from the simulations. The results from the analytic model remain unchanged. The distributions, as well as the number of free hydrogens per cluster, were shown in Figures 3, 4, and 5 of the original paper. The corrected versions of these figures are displayed below. The two major changes in the cluster distributions, visible in both Figures 3 and 5, are that the feature centered at a cluster size of four molecules has disappeared and that the distributions for the simulations at 297.3 K do not decay as quickly as in the original paper. The agreement between the cluster distributions calculated from the simulations and the analytic model, shown in Figure 5, is comparable to that seen for original distributions, although the agreement between the simulations and the analytic theory at large N for the two systems at 297.3 K is much improved. Figure 4, which shows the fraction of free OH groups per cluster as a function of cluster size, now indicates that clusters of size greater than one have slightly less than one free OH group per cluster. This suggests that a small fraction of the clusters are forming rings, but most of the clusters are chains. This differs from the original result that almost no clusters formed rings. Although the details of the corrected cluster distributions have changed from the original paper, the conclu-
Figure 4. Molecular dynamics simulations determining the number of free OH groups per cluster as a function of cluster size (N).
Figure 5. Comparison of molecular dynamics simulations to equilibrium model cases 2 and 3 for the two temperatures (297.3 and 413.2 K) and two pressures (0.55 and 2.65 kbar).
sion that the majority of hydrogen-bonded clusters in methanol are linear chains still holds and the development of the analytic theory based on this picture remains valid. Some other typographical errors appeared in the paper that we would like to take the opportunity to correct. Equation 6 should be
x1 )
Figure 3. Molecular dynamics simulations determining the mole fraction of monomers in clusters (xN) as a function of cluster size (N).
1 + 2eR - x1 + 4eR 2e2R
(6)
The correct version was used in all calculations. The pressure calculated during the simulation corresponding to the experiment at 297.3 K, 2.64 kbar was 6.56 kbar, not 8.56 kbar as reported in Table 1. JP9632899
20174 J. Phys. Chem., Vol. 100, No. 51, 1996
Additions and Corrections
1995, Volume 99 Alessandro Ferretti,* Alessandro Lami, Mary Jo Ondrechen, and Giovanni Villani: Role of Vibronic Coupling and Correlation Effects on the Optical Properties of MixedValent and Monovalent Dimer Compounds: The Creitz-Taube Ion and Its Monovalent Analogs Page 10484. While performing a new set of calculations, we discovered an error in the above-mentioned paper, due to a trivial input mistake. This concerns the absorption spectra in Figures 4a,b and 5. The correct figures are the following ones (same number as in the original paper).
Figure 5.
Figure 4.
The above figures pertain to the exact calculations of absorption spectra for the 4+ and 5+ species, with the model Hamiltonian (Hubbard + vibronic coupling) given in eq 1 of the paper. The main conclusions of the paper remain correct, but we have to mitigate somewhat our severity toward the approximate adiabatic model presented in the paper (see eq 11). The overall agreement between the exact spectra and the approximate adiabatic ones is not so bad, since the essential features of the spectra are reproduced. We apologize for the error. JP963231U
