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The Journal of Physical Chemistry. Vol. 92, No. 8, 1988
the C1- ion, which in turn is inversely proportional to the dielectric constant e. We can expect that acetone, having a smaller e, should give a larger K value as compared with acetonitrile and DMF. We notice that the equilibrium constants obtained from the chemical shifts differ considerably from those obtained from the line widths. Each of the K values evaluated from the line widths is smaller than the value of K from the proton shifts, and the former is one-third to one-half of the latter. The two experimental conditions used for the chemical shift and the line width measurements differ significantly from each other. In the case of the 'H chemical shift measurements, the C1- concentration was varied for the fixed low haloform concentration, but in the case of the line width measurements, the haloform concentration was varied for the fixed low C1- concentration. The implicitly assumed standard states (activity = l), which are extrapolated from real states, may be different for the two experimental conditions. In
Additions and Corrections other words, the two standard states for the chemical shift and the line width measurements may have different standard fugacities because the two experimental conditions can afford different proportional constants between fugacity and concentration. AGO and K depend on the choice of the standard state, and the different standard states will thus cause the disagreement between the two sets of K values obtained from the chemical shifts and the line widths. If one could take a common standard state and introduce the activity coefficients which are unity at the limit of zero concentration, then one would obtain the same equilibrium constant.
Acknowledgment. This research was supported in part by the Scientific Research Fund of the Japanese Ministry of Education (Grant 59540380). Registry No. C1-, 16887-00-6; CHCI,, 67-66-3; CHBr,, 75-25-2.
ADDITIONS AND CORRECTIONS 1987, Volume 91
T. Ebata,* A. Fujii, T. Amano, and M. Ito: Photodissociation of Formic Acid: Internal State Distribution of OH Fragment. Page 6096. There are errors in the determination of the rotational population distributions of the OH fragment. The correct versions of Figure 3 and Table I are as follows; nothing else in the paper is affected. However for a detailed discussion, see the forthcoming paper. TABLE I: OH Fragment Rotational Energy E , (cm-I) after the Photodissociation of HCOOH at Several Wavelengths Edissr
Eavail?
cm-'
cm-'
45 100 44 470 42 720 41 650 41 130 40 640
8900 8270 6520 5440 4930 4440
2&,2
EP
f,' 473.4 0.053 399.7 0.048 283.4 0.036 229.0 0.042 154.2 0.031 130.6 0.029
ratiod
2 b / 2
EP
f,'
446.0 358.4 235.0 143.5 131.6 77.1
0.051 0.044 0.037 0.027 0.028 0.018
(2nlj2/2n3/2)
0.79 0.92 0.63 0.60 0.54 0.40
"Available energy for the production of the 211312 level. For the production of the 211112level, the available energy decreases by 140 cm-I. bAveraged rotational energy. Fraction of the rotational energy (=Er/EavaiJ. dThe ratio of the total number of molecules in each spin sublevel.
IO N"
5
I
a2+PR12
a
l a , , 1
Figure 3.
H
,
, ouap, 5
P2tPQ12
10
N"
