Metastable states in NO2+ probed with Auger spectroscopy.

High-resolution N 1s and O 1s photoelectron spectra (PES) of NO are presented together with spectra of the subsequent Auger decay. The PES are analyzed by taking spin-orbit splitting of the (2)Π ground state into account providing detailed information on equilibrium distances, vibrational energies, and lifetime widths of the core-ionized states. In the Auger electron spectra (AES) transitions to five metastable dicationic final states are observed, with two of them previously unobserved. A Franck-Condon analysis of the vibrational progressions belonging to these transitions provides detailed information on the potential-energy curves of the dicationic final states as well as on the relative Auger rates. The present calculations of the potential-energy curves of NO(2+) agree well with the experimental results and allow an assignment of the two hitherto unresolved Auger transitions to excited states of NO(2+), C(2)Σ(+)and c(4)Π.

Valence photoelectron spectroscopy of N2 and CO: recoil-induced rotational excitation, relative intensities, and atomic orbital composition of molecular orbitals.

Recoil-induced rotational excitation accompanying photoionization has been measured for the X, A, and B states of N(2)(+) and CO(+) over a range of photon energies from 60 to 900 eV. The mean recoil excitation increases linearly with the kinetic energy of the photoelectron, with slopes ranging from 0.73×10(-5) to 1.40×10(-5). These slopes are generally (but not completely) in accord with a simple model that treats the electrons as if they were emitted from isolated atoms. This treatment takes into account the atom from which the electron is emitted, the molecular-frame angular distribution of the electron, and the dependence of the photoelectron cross section on photon energy, on atomic identity, and on the type of atomic orbital from which the electron is ejected. These measurements thus provide a tool for investigating the atomic orbital composition of the molecular orbitals. Additional insight into this composition is obtained from the relative intensities of the various photolines in the spectrum and their variation with photon energy. Although there are some discrepancies between the predictions of the model and the observations, many of these can be understood qualitatively from a comparison of atomic and molecular wavefunctions. A quantum-mechanical treatment of recoil-induced excitation predicts an oscillatory variation with photon energy of the excitation. However, the predicted oscillations are small compared with the uncertainties in the data, and, as a result, the currently available results cannot provide confirmation of the quantum-mechanical theory.

Analytical method for Buddleja colorants in foods.

Buddleja yellow colorant derived from Buddleja officinalis Maxim. has recently been approved for use as a new kind of natural colorant for food additives in China. In order to distinguish Buddleja yellow colorant from other yellow colorants, two known phenylpropanoid glycosides, acteoside (= verbascoside) and poliumoside, were isolated from the colorant as marker substances for Buddleja yellow colorant. Poliumoside has not been detected in B. officinalis Maxim. previously. These phenylpropanoid glycosides were not detected in the fruits of Gardenia jasminoides Ellis or in the stamens of the flowers of Crocus sativus L., which also contain crocetin derivatives as coloring components, using a photodiode array and mass chromatograms. Thus, an analytical HPLC method was developed to distinguish foods that have been colored with yellow colorants containing crocetin derivatives, using phenylpropanoid glycosides as markers.

Generation, Microwave Spectrum, Barrier to Internal Rotation of Methyl Group, and ab Initio MO Calculation of syn-2-Nitrosopropene, syn-CH(2)&dbond;C(CH(3))&bond;N&dbond;O.

syn-2-Nitrosopropene was generated, in the gas phase, by chemical reaction of 1-chloro-2-(hydroxyimino)propane with K(2)CO(3) and identified by microwave spectroscopy. The microwave spectrum of the reaction product was observed in the frequency range from 8.0 to 40.0 GHz. The rotational constants (MHz) were determined as A = 8744.09(6), B = 4846.07(2), and C = 3177.84(3) for CH(2)&dbond;C(CH(3))&bond;(14)NO (normal species) and A = 8664.36(5), B = 4822.15(3), and C = 3157.04(3) for CH(2)&dbond;C(CH(3))&bond;(15)NO ((15)N species) in the ground vibrational state. The values of the planar moment (P(cc) = (I(a) + I(b) - I(c))/2) obtained for the normal and (15)N species were 1.525(1) and 1.526(1) u Å(2), respectively. This suggests that the nitrogen atom lies in or is close to the ab inertial plane of the molecule and shows also that only two hydrogen atoms are located symmetrically out of the symmetry plane. The reaction product was determined to be syn-2-nitrosopropene by comparing the observed and calculated rotational constants, kappa (Ray's asymmetry parameter) and r(s) coordinates of the nitrogen atom. The dipole moments (D) were determined to be µ(a) = 2.43(5), µ(b) = 1.12(7), and µ(total) = 2.67(7). The barrier heights of the internal rotation owing to the methyl group of the normal species in the ground and first excited torsional states were determined to be 1750(50) and 1740(50) cal/mol (1 cal/mol = 4.184 J/mol), respectively. The (14)N nuclear quadrupole coupling constants (MHz) were determined to be chi(aa) = 0.25(21), chi(bb) = -7.11(40), and chi(cc) = 6.85(61). Two vibrational excited states were observed and the vibrational frequencies (cm(-1)) of the C-N and C-C torsional modes were determined to be 160(40) and 175(40), respectively. The lifetime of syn-2-nitrosopropene was found to be ca. 2 min in the waveguide cell. Copyright 2000 Academic Press.

[Empyema thoracis accompanied by hyperammonemic encephalopathy].

A 50-year-old man was admitted to our hospital due to consciousness disturbance. On admission, he was comatose (200 on the Japan Coma Scale) but brain computed tomographic (CT) scans were normal. Chest radiographs and CT scans on admission revealed massive pleural effusion in the right hemithorax. A culture of purulent pleural fluid yielded three species of anaerobes, including Bacteroides fragilis. Laboratory examinations revealed markedly elevated WBC count, CRP, and serum ammonia (586 micrograms/dl). However, liver function was almost normal and no other metabolic disorders were demonstrated. After the initiation of antibiotic therapy and pleural drainage, the patient's cousciousness level gradually improved in parallel with decreasing serum levels of ammonia and CRP. Because no other potential causes of hyperammonemia were observed, we concluded that the consciousness disturbance was due to hyperammonemia presumably caused by a urease-producing anaerobe infecting the right pleural space.

Microwave Spectrum and Molecular Conformation of (E)-Benzaldehyde Oxime.

The microwave spectrum of (E)-benzaldehyde oxime, C(6)H(5)-CH&dbond;NOH and C(6)H(5)-CH&dbond;NOD, has been observed in the frequency range from 26.5 to 40.0 GHz. The spectrum of the ground vibrational state was assigned and fitted to the Watson's A-reduced Hamiltonian to obtain these rotational and centrifugal distortion constants: A = 5183.13(29) MHz, B = 895.367(3) MHz, C = 763.819(3) MHz, Delta(J) = 0.019(3) kHz, and Delta(JK) = 0.204(7) kHz for the normal species, and A = 5158.4(23) MHz, B = 869.44(2) MHz, C = 744.34(2) MHz, Delta(J) = 0.023(2) kHz, and Delta(JK) = 0.193(7) kHz for the deuterated species. The values of the DeltaI (=I(c) - I(a) - I(b)) obtained for the normal and deuterated species were -0.295(6) and -0.28(5) a.m.u. Å(2), respectively. The molecular conformation of this molecule was a planar one in which the values of the dihedral angles, CCNO and CNOH, were almost 180 degrees and 180 degrees, respectively. Copyright 1999 Academic Press.

Microwave Spectrum and Molecular Conformation of delta-Valerolactam.

Microwave rotational spectra for normal and N-deuterated species of delta-valerolactam (2-piperidinone) were observed in the frequency range from 8 to 40 GHz. The spectra of the ground vibrational states for two isotopic species and the excited vibrational states for normal species were assigned, and the rotational constants (MHz) in ground vibrational state were determined using the Watson A-reduced Hamiltonian: A = 4590.96(11), B = 2495.03(2), C = 1731.06(2) for normal species and A = 4436.79(13), B = 2484.49(1), C = 1703.83(1) for deuterated species, respectively. The comparison of the rotational constants and r(s) coordinates of the imino hydrogen atom with ones from the ab initio MO calculation at the MP2/6-31G(d, p) level of theory led to the conclusion that the spectra assigned were due to a half-chair conformer. One vibrationally excited state was observed and its vibrational frequency was 95(64) cm(-1). Copyright 1999 Academic Press.

Generation, Microwave Spectrum, and Ab Initio MO Calculation of trans-1-Nitrosopropene, CH3CH&dbond;CH-NO (syn form).

trans-1-Nitrosopropene (syn form) was generated in the gas phase by pyrolysis of 1-chloro-1-methyl-2-(hydroxyimino)ethane and identified by microwave spectroscopy. The microwave spectrum of the pyrolysate was observed in the frequency range from 8.0 to 40.0 GHz. The rotational constants (MHz) were determined as A = 34 025(390), B = 2315.62(2), and C = 2198.54(2) for CH3CH&dbond;CH-NO (normal species) and A = 34 012(530), B = 2300.04(3), and C = 2182.70(2) for CH3CH&dbond;CH-15NO (15N isotopic species) in the ground vibrational state. The values of planar moment (Pcc = (Ia + Ib - Ic)/2) obtained for the normal and 15N isotopic species were found to be 1.62(10) and 1.52(13) uÅ2, respectively. These values are almost the same within the limit of errors. This suggests that the nitrogen atom lies in or is close to the ab inertial plane of the molecule and shows also that only two hydrogen atoms are located symmetrically out of the symmetry plane. The pyrolysate was determined to be trans-1-nitrosopropene by comparing the observed and calculated rotational constants, kappa (Ray's asymmetric parameter), and rs coordinates of the nitrogen atom. One vibrationally excited state was observed and assigned to the C-N torsional mode (158(50) cm-1). Interesting pyrolysates such as hydrogen cyanide and acetaldehyde were also detected during the pyrolysis of the precursor. The lifetime of trans-1-nitrosopropene is found to be ca. 5 s in the waveguide cell. Copyright 1999 Academic Press.

The Microwave Spectrum of n-Butyraldehyde Oxime.

The microwave spectrum of n-butyraldehyde oxime was observed in the frequency region 26.5-40 GHz. Four rotational conformers were found to exist in the gas phase; among these, two conformers belonged to the (E)-geometrical isomer and the other two to the (Z)-geometrical isomer. The microwave spectrum attributed to one of these two rotational conformers of (E)-butyraldehyde oxime was analyzed, and its rotational constants for the ground vibrational state were determined: A = 15883(379), B = 1269.97(1), C = 1251.60(1) MHz. The conformational structure of the molecule is discussed, referring to the rotational constants obtained and the ab initio molecular orbital calculation. Copyright 1998 Academic Press.