The implementation of a cell operating with the technique of Attenuated Total Reflection (ATR) enabled us to obtain good quality IR spectra of water for the whole region above 750 cmminus;1(which is the limit of the effect of the cutoff wave number of the crystal) and up to 5000 cmminus;1. ATR spectra have been recorded as a function of temperature ranging from minus;5thinsp;deg;C to 80thinsp;deg;C and ofH/Dmolar concentrationc(0c1). They have been transformed into spectra in egr;lsquo;, using the Bertiendash;Eysel iteration procedure. In this paper evolutions of these spectra in egr;lsquo;upon variations of these two parameterscandTare investigated and analyzed. It is shown that any experimental spectrum in egr;lsquo;of a mixture of normal and heavy water is a superposition of three spectra due to pure H2O, pure D2O, and a spectrum that is only slightly dependent upon isotopic concentrationcand is consequently mainly due to HDO. Analysis of this slight dependence uponcallows precise conclusions concerning vibrational interactions for both bending bands dgr; and stretching bands ngr;sto be reached. Evolution of spectra with temperature unambiguously shows that all spectra at temperatureTmay be decomposed into a low temperature spectrum and a high temperature spectrum. The coefficient defining this decomposition lsqb;Eqs. (11) and (14)rsqb; displays a quadratic variation withT. It is the same for H2O, D2O, and HDO within the precision of the experiment. A low temperature spectrum corresponding to a (slightly distorted) Hhyphen;bond network with no other defects, as well as a high temperature spectrum due to lsquo;lsquo;defectsrsquo;rsquo; cannot, however, be determined without any further assumption. Limits for values of the concentration of defects agr;(T) may nevertheless be established.
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