Raman spectroscopic evidence for increasing contact-ion pairing in the glassy states of “dilute” aqueous calcium nitrate solutions
✍ Scribed by Gerhard Fleissner; Andreas Hallbrucker; Erwin Mayer
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 604 KB
- Volume
- 218
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
Raman spectra of aqueous solutions of = 0.5 and GZ 0.05 M calcium nitrate recorded in their glassy states at 90 K are reported and compared with those recorded at 295 K. Evidence for increasing contact-ion pairing in the glassy state is based on increasing intensity of a band in the uq band region at z 740 cm-'. In the Y, band region two peaks can be resolved, with maxima at z 1049 cm-' for the contact-ion pair and at z 1036 cm-' for "free" nitrate. Relative intensities of bands due to "free" nitrate and contact-ion pair were determined by curve fitting the vq and vi band region. This curve fitting analysis shows that in the glassy state the molar intensities of "free" and contact-ion-paired nitrate cannot be equal in both spectral regions.