Water microwave spectrum

Orthonormality, 6 Orthonormal vectors, 86 Ortho water, 288 Oscillator strength, 307-308,313 OVC Cl method, 70, 245 Overtone band, 169 Overtone level, 252 Oxygen molecule localized MOs for, 104 microwave spectrum of, 221 rotational levels of, 191... 

Many investigations have been performed in order to elucidate the structure and bonding in cyclopentadienylthallium(I) compounds. Various bonding situations are found in this class. The parent compound, cyclopentadienyl-thallium (LHIa) is nearly unsoluble in polar solvents. It is rather stable to air and water and sublimable in a vacuum. The microwave spectrum (178) suggests a half-sandwich structure in the gas phase with a thallium to ring centroid distance of 2.41 A (see Fig. 11). The thallium-carbon distances of... 

In an earlier paper Bevan, Legon, Millen and Rogers 84) presented the microwave spectrum of the water-hydrogen fluoride complex. For the O... F distance they obtain d 2.68 0.01 A and for the dipole moment component along the symmetry axis 3.82 0.02 D. For v they gave, as a preliminary value, 198 cm-1 and for the out-of-plane and in-plane bridge vibrations 94 and 180cm-1, respectively. A full paper has been announced. 

Dyke TR, Muenter JS (1974) Microwave spectrum and structure of hydrogen-bonded water dimer. J Chem Phys 60 2929- 2930... 

In these molecules, two parameters, the O—H or S—O bond length and the interbond angle, must be determined from the data. The relation between the three moments of inertia and the total rotational energy cannot be expressed simply. The microwave spectrum of water is complex but has been analyzed to yield the bond distance and interbond angle. 

The microwave spectrum exhibits a tuimelling splitting due to a large amplitude internal rotation of the H2O subunit that exchanges bonded and non-bonded atoms. The internal rotor states are labelled with the asymmetric rotor quantum number for the rotational levels of free water (/tafc) and are designated as EOoo and Eloi 2 represents K=0 where K is the projection of the angular momentum of the water subunit onto the intermolecular axis. 

Among the more interesting examples of the use of this technique has been the analysis of methanol (methyl alcohol, CFI3OFI) in the presence of both ethanol (ethyl alcohol, CF13CFI20FI) and water (H2O). The former has a series of bands in the microwave spectrum lying between 29,636.91 and 37,703.67 MHz that are unique, and quantitative measurements of these have been used to determine the amount of methanol (methyl alcohol, CH3OH) in various samples of wine. ... 

Quantum mechanical and electromagnetic theory provide an additional extremely important restriction upon the occurrence of rotational transitions, namely, to a first and generally adequate approximation they can occur only for molecules having non-zero electric dipole moments. Thus, microwave spectra occur for the polar molecules of water, carbon monoxide and acetone but not for the non-polar moleculess of methane, carbon dioxide and benzene. It is worth stressing also that rotational spectra are produced only by gaseous molecules, not by liquids or solids. While this seems at first a serious limitation it should be noted that it is possible to vaporize even very refractory materials at elevated temperatures. Thus, the microwave spectrum of gaseous sodium chloride (Na-Cl) molecules is perfectly well known. 

Tubergen, M.J. Andrews, A.M. and Kuczkowski, R.L. (1993) Microwave spectrum and structure of a hydrogen-bonded pyrrole-water complex. J. Phys. Chem., 97, 7451-7457. 

Maser The microwave equivalent of a laser that represents some of the strongest transition intensities in the radio region of the electromagnetic spectrum, e.g. the water maser at 22.235 GHz. 

Examination of the ESR spectra measured in this study, Figures 1 and 2, shows no indication of the dipolar broadened line at 77 K in the networks studied even when the samples were cooled to 77 K from ambient temperature during more than four hours. We particularly checked the S-band spectra for this line. We expect the dipolar broadening to be the same at the two frequencies but much more conspicuous at S-band because the spectrum from isolated ions is spread over a smaller range of magnetic fields at this microwave frequency. The absence of the broad line indicates that in all the networks measured Cu(ll) hydrated by freezable, or bulk, water is not detected. These results are in agreement with those presented in ref. 25 which indicate the absence of bulk water in water absorbed on silica gels with pores smaller than 6 nm. 

Pramanik s group. He reasoned that the hydrolysis of dihydrohypoxanthine to 5-aminoimidazole-4-carboxamide (AIC) (see Scheme 19 and Figure 14 in Case Study 2) might be conveniently carried out using microwave irradiation. He dissolved dihydrohypoxanthine trifluoroacetate salt (81.1 mg) in 1 1 trifluoroacetic acid water (2 ml) and micronized the solution for 2 min at ambient pressure. After this time the electrospray-MS spectrum of the solution indicated that substantial AIC formation had occurred (Figure 1). 

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