Raman Spectrometry

Jones, Aubrey C.; Tunnicliff, Donald D.

doi:10.1021/ac60185a027

Cited by 7 publications

(6 citation statements)

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“…28 The vibrational spectroscopy is also an effective technique to investigate the associated species in nitrate solutions and many reports were presented. 15,[29][30][31][32][33][34][35][36][37][38][39][40] However, there is no consistent opinion for the existence and structure of the associated species. Peleg observed the Raman spectra of Mg(NO 3 ) 2 -H 2 O system in various concentrations and phase states.…”

Section: Introductionmentioning

confidence: 99%

Ab initio investigation on the ion‐associated species and process in Mg(NO₃)₂ solution

Zhang

2010

J Comput Chem

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In the present article, two focal subjects, i.e., hydration of the NO(3)(-) and associated ion species in the Mg(NO(3))(2) solution are researched by using the ab initio method. Nitrate ions with the hydration number of 1-6 are optimized at the HF/6-31+G* level. Their relative energies, binding energies, and v(1)-NO(3)(-) frequencies are also presented. The investigation of the binding energies shows the hydration number is 3-6 in the solvent abundant environment. The associated species, including ion pairings, triple- and multiple-ion clusters, are also optimized at the same level and their v(1)-NO(3)(-) frequencies are calculated for comparing with the results in experiments. From the comparison, the new associated process via aqueous free ions → solvent-shared ion pairings → solvent-shared triple and multiple ion clusters → contact multiple ion clusters → amorphous crystal is proposed.

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Section: Introductionmentioning

confidence: 99%

Ab initio investigation on the ion‐associated species and process in Mg(NO₃)₂ solution

Zhang

2010

J Comput Chem

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“…The instrumental performance and technique were considered to be adequate. Corrections to accurate Raman intensity measurements (1a) The refractive index correction I t is well known (Jones & Tunnicliff 1962) th at the intensity of a Raman band depends on the refractive index of the sample. Two effects are distinguished: (i) the geometrical-optical effect arising from reflectance and refractance losses, and (ii) the internal field effect which is the same as th a t encountered in infra-red spectroscopy (Rea 1959).…”

Section: Performancementioning

confidence: 99%

Dissociation of perchloric acid in aqueous solution at 25 °C

Covington

Tait

Wynne‐Jones

1965

Proc. R. Soc. Lond. A

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Quantitative Raman spectroscopy of electrolyte solutions can furnish direct evidence of the species present in concentrated solutions and their concentrations, but it is by no means easy to develop the photoelectric recording of the Raman intensities to yield measurements of sufficient accuracy. This has been achieved by Young at Chicago between 1948 and 1959; work which has been largely unpublished. The present paper describes the development and subsequent testing of apparatus in Newcastle for the photoelectric recording of Raman spectra to the high precision and reproducibility necessary. The principal requirements are a highly stable mercury arc light source and stable electronic amplification of the d.c. signal from the photomultiplier tube. Perchloric acid was chosen as the first system for quantitative study in view of doubts about the low value for the dissociation constant of 38 moles 1. -1 obtained by Redlich by n.m .r. spectroscopy, despite the apparent agreement with his earlier values of the degree of dissociation from photographic Raman studies. N.m .r. studies yield similar dissociation constants for nitric acid and perchloric acids. This is not in keeping with ideas about the strengths of these acids, and in particular conductivity measurements (Murray-Rust & Hartley 1929) show that perchloric acid is highly ionized in methanol whereas nitric acid is not. From studies of the intensity of the 931 cm -1 perchlorate ion line in perchloric acid solutions up to 11 M, values for the degree of dissociation (α) in the equilibrium H 2 O + HClO 4 ⇔ H 3 O + + ClO - 4 (1 - α)c αc αc were obtained by assuming that α is unity in the most dilute solution studied (0·3 M). This method obviates the use of a standard salt such as sodium perchlorate for comparison of the measured Raman intensities. The distinction is important in view of recent measurements which show that the integrated intensity of the nitrate ion band in aqueous solutions of metal nitrates is not strictly proportional to nitrate ion concentration (Vollmar 1963). The values of α obtained do not deviate significantly from unity until the molarity is greater than about 10 M, in which solutions there is insufficient water present to solvate the proton as H 9 O + 4 as in dilute solutions. The values obtained differ markedly from those from the n.m .r. studies, but it is suggested that the latter are incorrect being based on the naive assumption that the proton chemical shift does not vary as its solvation changes in solutions of increasing acid concentration.

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“…Intensity Measurement. The subject of the measurement of the intensities of Raman lines and their depolarization ratios was extensively reviewed two years ago (102). Among the more recent papers concerned with the measurement of Raman intensity is Golden and Crawford's (87) work on the measurement of absolute intensities in the gas phase.…”

Section: Resonance Raman Effectmentioning

confidence: 99%

“…Naberukhin showed that both correction factors are dependent upon both the refractive index and the sample and the depolarization ratio of the Raman line contrary to Rea's assumption that the influence of the depolarization ratio on the optical effect can be neglected. As has been pointed out by several investigators (102), the standard intensity scale becomes appropriate and convenient when exciting light polarized with its electric vector perpendicular to the direction of observation. For this case, Naberukhin found the correction factor to be appreciably simplified but still a func- tion of depolarization ratio.…”

Section: Resonance Raman Effectmentioning

confidence: 99%

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