Raman spectra data solution

The Raman spectrum of aqueous mer-cury(I) nitrate has, in addition to lines characteristic of the N03 ion, a strong absorption at 171.7 cm which is not found in the spectra of other metal nitrates and is not active in the infrared it is therefore diagnostic of the Hg-Hg stretching vibration since homonuclear diatomic vibrations are Raman active not infrared active. Similar data have subsequently been produced for a number of other compounds in the solid state and in solution. 

The spectra presented in Figures 1-3 demonstrate that high quality, transient resonance Raman spectra can be obtained for Ni(OEP) and Ni(PP) solutions using Soret excitation. These spectra can be interpreted on a molecular level by comparison with the extensive theoretical and experimental data base that exists for ground state nickel porphyrin species (8-16 and refs, therein). The coordination state of nickel porphyrins can easily be detetmined from the resonance Raman spectrum of the sample (10.12). Several modes in the Raman spectrum of porphyrins are quite sensitive to the state of axial ligation (10.12). In particular, the marker lines V4, 11 2> 3 10 (porphyrin skeletal mode designations follow those of Abe et al., (I2a). The designation... 

In situ Raman spectra of 2000 A PPy-GOD film, which was deposited on a GC electrode, were recorded in the 0.05 M PB (pH 7.4) solution. Figure 5 shows Raman spectra of the as-polymerized film and of those recorded at -1.0 V and +0.4 V. In the spectrum for the as-polymerized PPy-GOD film, there are several bands which may be due to the PPy (27, 30, 31) 922, 988, 1044, 1345, and 1552 cm"1. The 1345 cm"1 band could also be due to the GOD (2). However, there has been no clear evidence for the observation of resonance Raman spectrum of GOD itself (2), and the observed Raman spectrum for the as-polymerized PPy-GOD film may be totally due to the PPy. Virdee and Hester (30) have previously observed similar spectrum changes for a PPy-S04 film by applying the redox potentials. At any rate, the above spectroscopic data confirmed that the PPy-GOD film was formed on the GC electrode. Both UV-visible and Raman spectroscopic data were also consistent with the CV data, which indicated the presence of the redox reaction of the PPy in the PPy-GOD film. 

The Raman spectra are quicker and easier to determine than the infrared absorption spectra because ordinary optical equipment can be used, but frequently they are more difficult to interpret. The quantum restrictions in the two phenomena, particularly for symmetrical molecules, are not always the same, because the Raman spectrum involves an intermediate excited state of the molecule. For this reason, it is desirable to have the data of both Raman and infrared absorption spectra in order to determine completely the rotational and rotational-vibrational energy levels in the molecule. The Raman spectrum can be obtained in some solutions where direct absorption measurements are impossible because the solvent is opaque in the infrared. Aqueous solutions offer a good example of such a case. 

Early experiments with bacteriorhodopsin (228) interpreted the Raman spectrum in terms of an unprotonated Schiff base, forming a charge-transfer complex with a protein functional group (210,212). This interpretation of the Raman data, essentially based on a comparison with the frequencies of model Schiff bases in solution, was criticized by Honig and Ebrey (48), who pointed out that consistency could also be obtained with a protonated Schiff base model. The latter hypothesis was subsequently confirmed by deuteration experiments similar to those described for rhodopsin (229,230), and by Raman spectra in denatured systems (231). In variance with the clear-cut similarity observed between the resonance-Raman spectra of rhodopsin and isorhodopsin, and those of the 11-cis and 9-cis model compounds, respectively,... 

Some Properties of Xe(OSOtF)2.— Die Raman spectrum is compared with those of FXeOSOtF and StOoFt in Table III. Single crystals of Xe(OS02F)t were obtained by slow evaporation of a HF solution and fragmentary precession photograph data, from such a crystal, provided for the indexing of the X-ray powder data given in Table IV. The unit cell is monoclinic with a = 7.94, b = 13.7, c = 6.84 A, 0 = 96 . A small sample of Xe(OSOtF)2 under a dynamic vacuum at 20 slowly decomposed but none of the compound collected in the limbs of a U tube, cooled at —75°, provided to trap it. 

The infrared spectrum of quinazoline and other diazanaphthalenes were measured, and the vibrational fundamentals were assigned from Raman polarization data. The Raman spectrum of quinazoline in aqueous solution has fourteen bands that appear to be polarized. All the band frequencies, except for those at 1330 and 1334 cm were consistent with the frequencies assigned as fundamentals in the spectrum of naphthalene. The infrared spectra of several quinazolin-4(3H)-ones and their 3-acetyl, 3-acetoxy, and 3-hydroxy derivatives were examined at wave numbers lower than 3000 cm Bands due to NH stretching vibrations provided evidence for cyclic dimeric association between molecules. The zwitterionic structure (3) was proposed for 3-hydroxyquinazolin-4-one. ... 

IR and Raman spectra were recorded and assigned for 1,3-dioxolane (24) and a range of mono-, di- and trimethylated derivatives at an early date <59JCS807>. IR data for l,3-dioxolan-2-one (25) in solid, liquid, solution and vapor phases and its Raman spectrum have also been reported <56TFS1 178, 68JSP(27)285>, as have both IR and Raman spectra for l,3-dioxol-2-one (8) <70JST(5)67>. Other simple... 

Fig. 2.47. Unpolarized Raman spectrum of a frozen solution ofCeo in CS2at30 K. The solid line is a 3-Lorentzian fit to the experimental data. The highest frequency is assigned to the totally symmetric pentagonai-pinch Ag mode in The other two lines are assigned to the pentagonal-pinch mode in molecules containing one and two isotopes, respectively. The inset shows the evolution of these peaks as the solution is warmed [1548].

Figure 2 presents the Raman spectra of the precipitate and of the filtered Ni based solution. The Raman spectrum of the filtered solution with a main line at 960 cm" is assigned by reference to literature data [7] to condensed isopolymolybdate as Mog026] Such a formation is in agreement with the decrease of the pH observed upon addition of nickel nitrate in the HMA solution. Indeed for a Ni/Mo ratio equal to 0.5 the pH solution decreases from... 

Raman spectra have been reported for (CH3)2AsX and CH3ASX2 (X = Cl, Br, I) and in the case of the chlorides have been interpreted in terms of a decreasing As—Cl distance as CH3 is replaced by Cl [466). The Raman spectrum of (CH3)4AsCl in aqueous solution is consistent with a tetrahedral ion [467). Raman data are also available for (CH3)3As, CH3AsO(OH)2, and (CH3)2AsO(OH) [429, 467, 468, 469). 

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