Legendary Aphrodisiacs TO the Editor:
Didn't Waddell, e t al. ("Legendary Chemical Aphrodisiacs," J. CHEM. EDUC., 57, 341 (80)) overlook an important classmember? If memory serves me, L-dopa (I) received a lot of publicity in the early '70s for its (unwanted?) aphrodisiacal side effects in the treatment of Parkinson's disease.
Equation (2) is no more than the statement of an approximation for 2 - x. The approximation is if anything more complicated than the original, but I have no ouarrels so far with the derivation. (c) Introduce, without any explanation or justification,an empirical, adjustable constant k into (2)
NH.,
u being a unit of z and x (specificallycm-' in the paper). (d) Neglect, in equation (3,ln(zlu) relative toln(x/u),which is not justified since the original premise of equation (I) necessitates that the two logarithms have quite similar ualues. The final equation ([8] of the paper) then has the form
G. A. Cabat 3103 Silver Springs La Porte, TX 77571
whichseemingly allows the calculation ofz fromx. All this from one harmless little equation (I)! May I stress that I would have noobjections to equation (4) being used as an empirical equation.
To the Editor:
J. Lee
Mr. Cahat correctly points out that the potential aphrodisiac L-dopa was not discussed in our article. I imagine that many readers have a favorite which may or may not have been mentioned since, as was the paper, our brief review ". . . is not comprehensive." Also, the "Legendary" in the title might exclude L-dopa from discussion. Maybe we will compose a future paper "Modem Chemical Aphrodisiacs"; probably not, though-I think that I will get into enough trouble over the "Legendary." Thomas G. Waddell University of Tennessee at Chattanooga Chattanooga. TN
Computation Of Dissociation Energies To the Editor:
I wish to point out a serious problem with the derivation of eqn. (8) in the paper by K. Ramani and A. M. Ghodkaonkar ["Computation of Dissociation Energies of Diatomic Molecules," J. CHEM. EDUC., 58,609 (1981)l. Essentially the authors use the following algebraic procedure: (a) Start with a single equation (121 in the paper): (b) Extract an approximate y from eqn. (1)
University of Manchester Institute of Science and Technology Manchester M60 1QD.U.K.
To the Editor:
We have gone through the comments by Lee on our paper entitled "Computation of Dissociation Energies of Diatomic Molecules." At the outset it may be pointed that the equation derived by us was more or less based on the Pauling formula. T h e Pauling formula, however, does not include a group constant nor does it relate the correction factor to the dissociation energies of constituent molecules. Hence, the basis for giving a firm footing for the Pauling formula was undertaken, relating k to electronegativity. The Pauling formula as stated by us in eqn. (2) of our paper should have been redefined as where 4' = h A, h being the group const~tntand A is an excess of energy due tu heat u i reaction or ior~nation.Thrrct'ure, eqn. (6) should have heen written in terms of 1'ns iollows: The confusion about an arbitrary introduction of k would have been avoided as pointed out by Lee. This omission has inadvertently crept into the paper. The final equation (eqn. [a]) would follow naturally, with the simplifying assumptions made in the paper. The paper was meant to provide a physical insight into the nature of computation of dissociation energies and not to highlight any mathematical rigor. The agreement between the calculated and experimental values indicates the soundness of our approach. K. Ramani and A. M. Ghodkaonkar
Western Regional Instrumentation Center University of Bombay
and substitute this into (1)
Bombay, India 400 098
Volume 59
Number 7
July 1982
623
