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1.
Integral scattering cross sections have been measured for alkali ions (Li+, Na+ and K+) in the energy range 500–4000 eV scattered by room temperature N2 and CO molecules through effective laboratory angles greater than 5 × 10?3 rad. The repulsive potentials deduced from the cross sections are represented bya practically identical formula for the Na+N2 and Na+CO systems, and for the K+CO systems, respectively, while the repulsive potentials of the Li+N2 system are somewhat smaller than those of the Li+CO system at larger intermolecular distances.  相似文献   

2.
An improved theory of electron transfer absorption is proposed. The possibility of such absorption during the collision of ion-molecule pairs is discussed and frequencies for the O2O2+, O2O2?, NONO?, COCO+ and N2N2+ pairs are estimated. Oscillator strengths are also estimated for the O2O2+ pair.  相似文献   

3.
Time-resolved measurement of He (2 3S) concentration by its optical absorption after electron pulse irradiation of HeN2 mixtures confirms that the optical emission of N+2(B 2Σ+u → X 2Σ+g) is based on the energy transfer (Penning ionization) from He (2 3S) to N2. The addition of other atoms and molecules to HeN2 mixtures changes the decay rate of the optical emission N+2(B 2Σ+u → X 2Σ+g), which is a detector of He (2 3S), and gives the rate constant of He (2 3S) de-excitation by various atoms and molecules. Our results are discussed from the viewpoint of a gas-kinetic collision model.  相似文献   

4.
Absolute emission cross sections have been determined for electron impact on CO, NO and N2. For the CO(A 1ΠX 1Σ+) and N2(a 1ΠX 1Σg) radiation our data is in good agreement with that of other groups. For CO+ (B2Σ+X2Σ+) the values of the emission cross sections are different from those measured previously. This discrepancy is explained in terms of an inadequate straylight correction in the former experiments. For the NO(A2Σ+X2Π) emission no previous σem values are known to the authors. Furthermore the electronic transition moments of the NO(A2Σ+X2Π) and CO+(B2ΣX2Σ+) systems have been measured and are found to be independent of the internuclear distance.  相似文献   

5.
Strongly enhanced N2 first positive emission N2(B 3Πg → A 3Σ+u) has been observed on addition of N atoms into a flowing mixture of Cl and HN3. The dependence of the emission intensity on N atom concentration gave a rate constant for the reaction N + N3 → N2(B 3Πg) + N2(X 1Σ+g) of i(1.6 ± 1.1) × 10?11 cm3 molecule?1 s?1. That for the reaction Cl + HN3 → HCl + N3 is (8.9 ± 1.0) × 10?13 cm3 molecule?1 s?1 from the decay of the emission. Comparison of the emission intensity in ClHN3 with that in ClHN3N gave the rate constant of the reaction N3 + N3 → N2(B 3Πg) + 2N2(X 1Σ+g) as 1.4 × 10?12 cm3 molecule?1 s?1 on the assumption that N + N3 yields only N2(B 3Πg) + N2(X 1Σ+g).  相似文献   

6.
Pyridine N-imine complexes of methylcobaloxime, CH3Co(Hdmg)2(R1— C5HnN+N?H) (n = 4; R1 = H, 2-CH3, 3-CH3, 4-CH3: n = 3; R1 = 2,6-CH3), have been synthesized by the reaction of CH3Co(Hdmg)2S(CH3)2 with a pyridine N-imine which is generated from a pyridine, hydroxylamine-O-sulfonic acid and K2CO3. The reactions of CH3Co(Hdmg)2(C5H5N+N?H) with acid anhydrides form new methylcobaloxime complexes with N-substituted pyridine N-imines, CH3Co(Hdmg)2(C5H5N+N?R2) R2 = COPh, COMe, COEt). With maleic anhydride, (pyridine N-acryloylimine)carboxylic acid is formed. With acetylenedicarboxylic acid dimethyl ester, 1,3-dipolar cycloaddition of the ligand gives pyrazolo[1,5-a]pyridine-2,3-dicarboxylic acid dimethyl ester.  相似文献   

7.
The 13C chemical shifts, the 13C31P coupling constants, and some one-bond 13C1H coupling constants were measured for the title compounds. For the ylides of phosphorus, arsenic and sulfur, the data are consistent with an sp2-hybridized ylidic carbon with a strong, localized negative charge, while for the pyridinium ylide this charge is much more delocalized. in the homologous series of salts the electron-withdrawing ability of the groups studied varies in the order: Ph3P+ < Ph3As+ « Me2S+ « Me2C5H3N+. The differences in the carbonyl chemical shift between the ylides and the corresponding salts are a measure of the resonance stabilization of the negative charge in the form X+CCO?; this stabilization varies with the groups studied in the order: Ph3P+ < Ph3As+ ≈ Me2S+ « Me2C5H3N+. The ylide—palladium(II) complexes contain a bond between the ylidic carbon and the metal: the ylidic carbon is shifted upfield in the complex with respect to the free ligand, while the adjacent carbonyl is shifted strongly downfield. These data suggest that the PdC(1) bond is strongly polarized with a high electron density on the C(1) atom which cannot be delocalized through resonance as in the free ligands.  相似文献   

8.
A sudden approximation recently derived by Cross using a semiclassical treatment of the orbital motion is recast into a form which permits factorization of differential and integral degeneracy averaged cross sections, opacities as a function of final angular momentum quantum number, the scattering amplitude, and the phenomenological cross section which describes spectral line broadening. Calculations are done using an average of initial and final orbital angular momentum quantum numbers for the partial wave parameter for ArN2, ArTIF, H+H2 and Li+H2. The results indicate that the method is a good approximation for integral cross sections and opacities when the energy sudden approximation is valid and when the coupling of the orbital motion is important.  相似文献   

9.
We have measured the ionic conductivities of pressed pellets of the layered compounds MUO2PO4 · nH2O, and correlated the results with TGA data. The conductivities (in ohm?1 m?1), at temperatures increasing with decreasing water content over the range 20 to 200°C, were approximately as follows: Li+4H2O, 10?4; Li+, Na+, K+, and NH4+3H2O, 10?4, 10?2, 10?4, and 10?4; H+, Li+, and Na+1.5H2O, 10?2, 10?4, and 10?4; Na+1H2O, 10?5; H+, K+, and NH4+0.5H2O, all 10?5; and H+, Li+, Na+, K+, NH+4, and 12Ca2+OH2O, 10?5, 10?5, 10?4, 10?5, 10?5, and 10?6. A ring mechanism is proposed to account for the high conductivity found in NaUO2PO4 · 3.1H2O. The accurate TGA data showed that most of the hydrates had water vacancies of the Schottky type, and should be represented as MUO2PO4(A ? x)H2O, where x can be between 0 and 0.3.  相似文献   

10.
Silicon atoms react under single collision conditions with N2O to yield chemiluminescent emission corresponding to the SiO a3Σ+?X1Σ+ and b3Π?X1Σ+ intercombination systems and the A1Π?X1Σ+ band system. A most striking feature of the SiN2O reaction is the energy balance associated with the formation of SiO product molecules in the A1Π and b3Π states. A significant energy discrepancy ( = 10000 cm? = 1.24 eV) is found between the available energy to populate the highest energetically accessible excited-state quantum levels and the highest quantum level from which emission is observed. It is suggested that this discrepancy may result from the formation of vibrationally excited N2 in a concerted fast SiN2O reactive encounter. Emission from the SiO a3Σ+ (A1Π) and b3Π(A1Π, E1Σ0+) triplet-state manifold results primarily from intensity borrowing involving the indicated singlet states. Perturbation calculations indicate the magnitude of the mixing between the b3Π, A1Π and E1Σ0+ states ranges between 0.5 and 2%. On the basis of these calculations, the branching ratio (excited triplet)/(excited singlet) is found to be well in excess of 500. An approximate vibrational population distribution is deduced for those molecules formed in the b3Π state. The present studies are correlated with those of previous workers in order to provide an explanation for diverse relaxation effects as well as observed changes in the ratio of a3Σ+ to b3Π emission as a function of pressure and experimental environment. Some of these effects are attributable to a strong coupling between the a3Σ+ and b3Π state. Based on the current results, there appears to be little correlation between either (1) the branching ratio for excited state formation or (2) the total absolute cross section for excited-state formation and (3) the measured quantum yield for the SiN2O reaction. Implications for chemical laser development are considered.  相似文献   

11.
Carrier-mediated cation fluxes were determined using a H2OCHC13H2O liquid merebrane system for TlNO3 and for binary mixtures of either TlNO3 or KNO3 with alkali metal ions, alkaline earth metal ions, and Pb2+ (in the case of TlNO3). Both macrocyclic polyether and cryptand ligands were used as carriers. In Tl+Mn+ mixtures, selective transport of Tl+ was found over all cations studied, except in the cases of Ag+ by 2.2 and of Pb2+ by 18C6, DC18C6, ClDKP18C6, and 2.2. Generally, K+ was transported selectively from K+Mn+ mixtures, except in the cases of K+Tl+ mixtures in which Tl+ was transported selectively in all cases. A model relating cation flux to log K(CH3OH) for Mn+—macrocycle interaction and to ion-partitioning between the organic and aqueous phases was successful in rationalizing selective cation transport in most of the systems studied.  相似文献   

12.
The mechanism of uv (λ > 325 nm) photodegradation of polypropylene (PP) containing N,N,N′,N′-tetramethyl-p-phenylenediamine (T4MPD) has been investigated by means of ESR spectroscopy. The observed spectra after uv irradiation of both isotactic-PP (IPP) and stereoblock-PP (SPP) samples in vacuum at 77 K consisted principally of a broad singlet which was assigned to a T4MPD cation radical (T4MPD). On the other hand, the spectrum observed after irradiation of an atactic polypropylene (APP) sample at 77 K in vacuum was resolved into several components which decayed almost up to ca. 263 K to give rise to the broad singlet of T4MPD. One component was a sharp quartet which was assigned to a methyl radical, ·CH3·. The other component, a singlet, was attributed to a trapped electron, et?.By comparison of the ESR spectrum of deuterated T4MPD with that of the normal compound it was found that 60 ~ 70% of the methyl radicals arose from the added T4MPD due to β-scission, which also formed the N,N,N′-trimethyl-p-phenylenediamine radical, T3MPD·. The T3MPD· radical presumably captures an electron at lower temperatures to become a carbanion, T3MPD?, which releases the electron to reproduce the T3MPD· radical at elevated temperatures. This production of the radical T3MPD· due to the liberation of an electron provides an explanation for the observed increase in intensity of the decay curve in the temperature range from ? 168 K to 185 K. The remaining fraction, 30 ~ 40%, of the total methyl radicals was produced from the PP matrix by an energy transfer from the excited T4MPD1 to the PP matrix. The broad singlet which appeared in the temperature range near 195 K was attributed to an acyl radical ~CH2CH(CH3)CH2?O from the observed g-value. By photoillumination of this sample this broad singlet was converted reversibly into the quartet which was assigned to the radical ~CH2CH(CH2·)CH2CHO.  相似文献   

13.
[C5H5Fe(CO)2thf]+ reacts with the ligands LL and LLL to give the cations [C5H5Fe(CO)2LL]+ (LL = RS(CH2)nSR, 1,4-dithiane) and [C5H5Fe(CO)2LLL]+ (LLL = 1,3,5-trithiane, tris(methylmercapto)methane) containing monodentate coordinated sulfur ligands. In a similar way, sulfur ligand bridged dinuclear dications [(C5H5Fe(CO)2)2(μ-LL)]2+ and [(C5H5Fe(CO)2(μ-LLL)]2+ and tri-nuclear trications [(C5H5Fe(CO)2)3(μ-LLL)]3+ are formed. Irradiation of the mononuclear cations gives the chelate complexes [C5H5Fe(CO)(η2-LL)]+.  相似文献   

14.
The preparations of CH2SF4 and CH3CHSF4 are presented and the structures are discussed. Addition reactions of polar species give a wide range of new compounds, like Hg(CH2SF5)2, F4AsCH2SF5, cisBrSF4CH3, cisF5SeOSF4CH2Br, a.o. While CH2SF4 decomposes at room temperature slowly to CH2CH2 and SF4, at high temperatures HF and CSF2 are formed. CH3CHSF4 gives mainly CH3CHF2 at room temperature. The “saturated” compounds CH3SF5 and C2H5SF5 have been prepared. They react with SbF5 in SO2 at low temperatures to form the cations CH3SF4+ and C2H5SF4+. The CH3SF4+ ion has been investigated in detail by nmr methods at low temperatures. It decomposes to CH3 and SF4, which react further in the SO2/SbF5 system to CH3OSO+ and SF3+.  相似文献   

15.
IR spectra are plotted from anilides of 1-piperidine carboxylic acids C5H10N(CH2)n CONHC6H4R in CHCl3 and CDCl3 solutions. In the cases of n = 1 and n = 4, weak intramolecular (NH?N) hydrogen bonds are formed. An asymmetrical energy surface occurs and the proton is present at the N of the anilide group. In the cases of n = 2 and n = 3, intramolecular proton transfer hydrogen bonds of the types NBH?NP ? ?NB?H+Np are formed. In contrast to the intramolecular OH? N ? O?1 ? H+N bonds with 1-piperidine carboxylic acids, these bonds to not cause IR continua but two bands: one in the region 3250–3190 and one in the region 2500–2450 cm?1. The fact that, instead of IR continua, bands are observed is explained by the following: (1) these hydrogen bonds are relatively long; (2) they show only a narrow distribution of bond length; (3) the electrical fields at these bonds are small, since they are strongly screened.  相似文献   

16.
Resonance and preresonance Raman spectra have been obtained in the region 400–1700 cm−1 for some benzothiazolium and indolinium steryl dyes containing a crown ether ring. Spectra arising from the trans isomers are observed selectively due to the resonance effect, and the principal features can be attributed to modes of the central conjugated PhN+CCCPh unit present in each of these molecules. Complex formation between the dye molecules and Mg2+ in acetonitrile solution results in intramolecular electron transfer. This is observed in the Raman spectra as a downshift of a band assigned to PhO vibration in the crown ether unit, and upshifts of several bands associated with the PhN+CCCPh unit, including the phenyl ring, CC and +NC stretches. The results demonstrate the sensitivity of the Raman spectra to changes in the structure and bonding within these photochromic complexing agents on binding to metal ions, and indicate that they may serve as a useful probe for the complicated photoisomerization and complexation reactions of these interesting systems.  相似文献   

17.
Raman and infrared spectra of tiapride were recorded from 4000 to 200 cm−1. Assignments of the fundamental vibrations involved in intra or intermolecular H-bonds as NH⋯O, N+H⋯O and N+H⋯Cl are discussed. Analysis of some characteristic vibrations leads to the conclusion that the conformations are quite independent of the solvent effects. The change from tiapride base to chlorhydrate that occurs during the crystallization involves a new order of the aliphatic chain which changes the planarity of the chelated form.  相似文献   

18.
C. Broquet 《Tetrahedron》1973,29(22):3595-3598
The enolate ylide Ph3P+C?C(Ph)O?Li+ obtained by the reaction of HMPT-Li with the benzoylmethylenetriphenylphosphorane Ph3PCHCOPh reacts with aliphatic ketones, in contrast to its precursor. This condensation makes it possible to prepare β,γ-unsaturated ketones, of type RCHC(R′)CH2COPh, instead of the α,β isomer usually obtained in a Wittig reaction.  相似文献   

19.
Mercuration of η5-cyclopentadienyl-η4-tetraphenylcyclobutadienecobalt, followed by transmetalation with n-butyllithium and reaction of the lithium derivative with benzophenone gave η4-Ph4C4Coη5-C5H4CPh2OH. Treatment of this alcohol produced the [η4-Ph4C4CoC5H4CP2]+ cation. This species reacted as a carbon electrophile with methanol, monomethylamine and N-methylpyrrole, as a cobalt electrophile with N,N-dimethylaniline and anisole. In the latter process the C5H4CPh2 ligand was displaced and the η6-arene-η4-tetraphenylcyclobutadienecobalt complexes were formed. Similar reactions with benzene, toluene and mesitylene proceeded only in the presence of aluminum chloride. The bonding in the cation is discussed on the basis of this chemistry and 13C NMR studies.  相似文献   

20.
《Chemical physics》1987,112(3):363-372
A spectroscopic characterization of a N2 radiofrequency discharge and N2CO post discharge has been performed. The relative vibrational distribution of the excited B 3Πg and C 3Πu states of nitrogen and their correlation with the ground state have been analyzed. The analysis confirms the importance of the metastable molecules. N2(A 3Σ+u), in affecting the vibrational distribution of nitrogen in its ground state in the discharge and post discharge. The vibrational analysis of the CO ground state, excited in the post discharge by vibrationally excited N2 molecules, confirms the high degree of vibrational non-equilibrium in the ground state of nitrogen, in the presence of a low first-level vibrational temperature.  相似文献   

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