Spectra far infrared

The He I photoelectron spectrum of the NH2(X Bi) radical, produced from the fast reaction F +NH3NH2 + HF, shows three bands corresponding to the ionization of NH2 to the X Bi, a Ai, and b Bi states of NH2 (see p. 240). The sharp band at 12.45 eV has two vibrational components, separated by 1350 50 and 2900 50 cmwhich were assigned to the excitation of both the V2 and Vi vibrations in the ionic state a Ai. The band at 12.00 eV shows regular vibrational spacings on the low ionization potential side which were attributed to the excitation of the V2 mode of NH J (X Bi). Studies of spectra of the deuterated radical supported the assignments. 

In the microwave absorption (MW) spectrum the fine and hyperfine components of the 3i,3 22,o ( 2 lines) and 1i,o 1o,i(9 lines) rotational transitions in the X Bi(0,0,0) state were measured in the range 230 to 469 GHz (7.67 to 15.36 cm ). The lines which lie in the atmospheric windows near 231 GHz and between the water lines at 448 and 471 

Magnetic-dipole-allowed transitions between the spin doublets Fi(J) and p2(J) in the X Bi ground and the A Ai excited electronic states were observed in microwave optical double resonance (MODR) spectra in the frequency range 30 GHz (1 cm ). In addition, a few MODR bands were identified as electric-dipole-allowed transitions in the ground state X Bi which have three to four orders of magnitude stronger transition rates than the magnetic-dipole-allowed MW transitions [4]. 

MODR signals were obtained by pumping the appropriate optical transitions, A Ai(0,10,0) 4-X Bi(0,0,0) at about 17500 cm and A Ai(0,9,0) X Bi(0,0,0) at about 16600 cm with a Rhodamine 6G dye laser. The majority of the MODR bands observed were assigned to the magnetic-dipole-allowed transitions between Fi and F2 spin components for a rotational state Nk Kc e vibronic ground state X Bi(0,0,0) [4 to 7] and in the excited vibronic states A Ai (0,9,0) with Kg = 0 and A Ai (0,10,0) with Kg = 1 [8]. The 

Magnetic-dipole-allowed transitions. - Electric-dipole-allowed transitions, frequencies [4, 9, 10] were used for the fitting procedure. - The 33,i(J = 7/2) 4i,3(J = 7/2) and 33,i(J = 7/2) a result of the spin-rotation interaction mixing of level 4 3(0 = 7/2) with level 33 i(J = 7/2). 

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Venables D S and Schmuttenmaer C A 1998 Far-infrared spectra and associated dynamics in acetonitrile-water mixtures measured with femtosecond THz pulse spectroscopy J. Ohem. Rhys. 108 4935-44... 

Over the next few years, both the mid-infrared and the far-infrared spectra for Ar-HF and Ar-HCl were extended to numerous other bands and to other isotopic species (most importantly those containing deuterium). In 1992, Hutson [18, 39] combined all the available spectroscopic data to produce definitive potential energy surfaces that included both the angle dependence and the dependence on the HF/HCl monomer vibrational quantum number v... 

Fig, 37. Far-infrared spectra of chromium, iron, and cobalt atom reactions with benzene, benzene-(f and benzene/benzene-d mixtures in argon matrices at 10-12K 171). 

Examinations of the far-infrared spectra of solutions of Zr (allyl) 3CI and Zr (allyl) 2CI2 (9) suggest that the former exists in solution as the dimer (X), whereas the latter has the monomeric structure (XI). A broad intense peak at 244 cm-1 can be assigned to zirconium-bridging chlorine stretching mode. This band is completely absent from the spectrum of the dihalide and is replaced by a very strong band at 342 cm-1 due to the nonbridging chlorine. 

T. Lo, I.S. Gregory, C. Baker, P.F. Taday, W.R. Tribe and M.C. Kemp, The very far-infrared spectra of energetic materials and possible confusion materials using terahertz pulsed spectroscopy , Vib. Spectrosc. 42 (2006) 243—248. 

Table 3. Characteristic absorption bands of visible, infrared, and far-infrared spectra and magnetic susceptibility of pendant-type polymer-Co(III) and -Cr(lII) complexes... 

Consequently, these charge effects are reflected in the carbonyl stretching frequencies (87, 88). It has recently been found from studies of the far infrared spectra that the metal-carbon stretching frequencies also support the theory (89). These charge-distribution effects are supported further by the observed dipole moments (90-92). Thus the dipole moments of the chromium tricarbonyl complexes of hexamethylbenzene, benzene, and methylbenzoate lie in the order 6.22, 4.92, and 4.47 /x, respectively. The relationship of charge effects to chemical reactivity is described below. 

G. Birnbaum. Determination of molecular constants from collision-induced far-infrared spectra and related methods. In J. van Kranendonk, ed., Intermolecular Spectroscopy and Dynamical Properties of Dense Systems - Proceedings of the International School of Physics Enrico Fermi , Course LXXV, p. Ill, 1980. 

G. Birnbaum and E. R. Cohen. Determination of molecular multipole moments and potential function parameters of non-polar molecules from far infrared spectra. Molec. Phys., 32 161, 1976. 

L. Frommhold, R. Samuelson, and G. Birnbaum. Hydrogen dimer structures in the far-infrared spectra of Jupiter and Saturn. Astrophys. J., 283 L79, 1984. 

D. Gautier, A. Marten, J. P. Baluteau, and G. Bachet. About unexplained features in the Voyager far infrared spectra of Jupiter and Saturn. Can. 

A. R. W. McKellar. Experimental verification of hydrogen dimers in the atmospheres of Jupiter and Saturn from Voyager IRIS far-infrared spectra. Astrophys. J., 326 L75, 1988. 

For diorganotin dicarboxylates, the symmetrically chelated structure has been proposed from infrared and far-infrared spectra (9). A nonsymmetrically chelated configuration and a partial bridging of acetoxy groups have also been proposed based on infrared data (10, 11). 

Infrared data have been tabulated for benzotriazole and a wide range of its transition metal complexes or adducts (172). Far infrared spectra have been recorded for copper(II) benzotriazole adducts and bands at 270-320 cm-1 have been assigned to Cu-N vibrations (172). Infrared absorptions at approximately 825, 800, and 775 cm-1 in the spectra of cobalt(III)/4,5-disubstituted triazolate complexes have been attributed to triazolate ring vibrations (109). Infrared data have been reported and assignments made for palladium and platinum thiatriazoline-5-thionate complexes (37) and for the parent thione (127). Vibrational spectroscopy has been employed in an attempt to determine coordination sites for a range of 8-azapurine complexes (108). 

The far infrared spectra of the phenanthroline complexes show two distinct patterns [300] in the 240—170 cm-1 region. The lighter members, La to Sm, show spectra which have several strong to medium bands located from 175 to 220 cm-1 (Table 26). With Eu to Lu several strong bands are observed in the 235 cm-1 region. 

MOLECULAR MODELS FOR CALCULATION OF DIELECTRIC/FAR-INFRARED SPECTRA OF LIQUID WATER... 

D. Quite another approach, as compared with Refs. 7 and 12b was proposed in Refs. 6 and 8 in terms of a semiphenomenological molecular model capable of describing the wideband dielectric and far-infrared spectra of ordinary and heavy water. In the model the total dipole-moment vector was presented as a sum of two components. The absolute value p of the first component is set constant in time the second component, p(f), changes with time harmonically. Such rather formal presentation of a total dipole moment ptot is possibly a simplest step in taking account of the collective effects, since a time-varying dipole moment p(f) arises due to cooperative motion of nearby polar water molecules. 

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