A solution of the DGLAP equation for gluon at low x

We obtain a solution of the DGLAP equation for the gluon at low x first by expanding the gluon in a Taylor series and then using the method of characteristics. We test its validity by comparing it with that of Glück, Reya and Vogt. The convergence criteria of the approximation used are also discussed. We also calculate εF ₂(x,Q)²/ε In Q ² using its approximate relations with the gluon distribution at low x. The predictions are then compared with the HERA data.     

O-atom transport catalysis by atomic cations in the gas phase: reduction of N2O by CO

Atomic cations (26), M+, have been shown to lie within a thermodynamic window for O-atom transport catalysis of the reduction of N2O by CO and have been checked for catalytic activity at room temperature with kinetic measurements using an inductively-coupled plasma/selected-ion flow tube (ICP/SIFT) tandem mass spectrometer. Only 10 of these 26 atomic cations were seen to be catalytic: Ca+, Fe+, Ge+, Sr+, Ba+, Os+, Ir+, Pt+, Eu+, and Yb+. The remaining 16 cations that lie in the thermodynamic window (Cr+, Mn+, Co+, Ni+, Cu+, Se+, Mo+, Ru+, Rh+, Sn+, Te+, Re+, Pb+, Bi+, Tm+, and Lu+) react too slowly at room temperature either in the formation of MO+ or in its reduction by CO. Many of these reactions are known to be spin forbidden and a few actually may lie outside the thermodynamic window. A new measure of efficiency is introduced for catalytic cycles that allows the discrimination between catalytic cations on the basis of the efficiencies of the two legs of the catalytic cycle. Also, a potential-energy landscape is computed for the reduction of N2O by CO catalyzed by Fe+(6D) that vividly illustrates the operation of an ionic catalyst.     

Existence of doubly charged lead monohydrate: experimental evidence and theoretical examination

Despite reports to the contrary, doubly charged lead monohydrate is a stable species against both proton and charge transfers. [Pb(H(2)O)](2+) has been observed as a minor product in the ligand-exchange reaction of [Pb(CH(3)CN)](2+) with H(2)O after collisional activation. Density functional theory has been used to examine reaction profiles of [Pb(H(2)O)(n)](2+) where n = 1, 2, and 3.     

A flowing afterglow study of [C3H3]− ions generated from the reactions of [OH]− with allene and propyne

Flowing afterglow studies are reported for the rates and modes of reaction of [C₃H₃]^? ions produced from allene and propyne by reaction with [OH]^? or by electron impact. Studies with methyl formate provide further evidence for the formation from propyne of two distinct stable species.     

Overtone spectroscopy of some benzaldehyde derivatives

Overtone spectrum of o, m and p-nitrobenzaldehydes and p-chlorobenzaldehyde has been studied in 2000–12000 cm⁻¹ region. Vibrational frequencies and anharmonicity constants for aryl as well as alkyl CH stretch vibrations have been determined. We have also determined the internuclear distances for the aryl CH bond in the different molecules. The small variation observed in these distances is an indication of the substitution effect. It is observed that in the case of p-disubstituted benzens, the shift in aryl CH bond is proportional to sum of the Hammet σ of the substituents. However in the case of o-disubstituted benzenes it is only 80% of the para-substituted shift.     

Generation and dissociation of oxygen‐ and chloride‐bridged iron(III) and manganese(III) tetraphenylporphyrin dimer ions in the gas phase

Electrospray ionization mass spectrometry (ESI/MS) has allowed the discovery of novel dimer ions emerging from solutions of metalloporphyrin salts and their investigation by collision‐induced dissociation (CID) with N₂ molecules. ESI mass spectra have been recorded for the formation of the oxygen or chloride‐bridged dimer ions [(FeTPP)₂OH]⁺, [(MnTPP)₂OH]⁺, [(FeTPP)₂Cl]⁺ and [(MnTPP)₂Cl]⁺ derived from various solutions of FeTPPCl and MnTPPCl salts. The CID of [(FeTPP)₂OH]⁺ proceeds mainly by neutral loss of (FeTPP)OH to form [FeTPP]⁺ and, to a minor extent, to form the charge‐reversed products. The CID of [(MnTPP)₂OH]⁺ exhibits exclusively the product ion [MnTPP]⁺ by loss of neutral (MnTPP)OH. [(FeTPP)₂Cl]⁺ and [(MnTPP)₂Cl]⁺ dissociate by loss of (Fe/MnTPP)Cl to give rise to [Fe/MnTPP]⁺. [(FeTPP)₂O]⁺ and [(FeTPP)₂OH]⁺ were generated from a solution of the dimer, (FeTPP)₂O. Dissociation of [(FeTPP)₂O]⁺ yields two product ions, [FeTPP]⁺ and [(FeTPP)O]⁺, with higher onsets compared to the equivalent fragments formed from [(FeTPP)₂OH]⁺. Copyright © 2009 John Wiley & Sons, Ltd.     

Identification of a higher-order organozincate intermediate involved in Negishi cross-coupling reactions by mass spectrometry and NMR spectroscopy

Negishi cross-coupling reactions were analyzed in solution by mass spectrometry and NMR spectroscopy to identify both the effect of LiBr as an additive as well as the purpose of 3-dimethyl-2-imidazolidinone (DMI) as a co-solvent. The results suggest that the main role of DMI is to facilitate a higher order bromozincate formation during the addition of LiBr.     

Mass spectrometric study of the dissociation of Group XI metal complexes with fatty acids and glycerolipids: Ag2H+ and Cu2H+ ion formation in the presence of a double bond

Results of mass spectrometric studies are reported for the collisional dissociation of Group XI (Cu, Ag, Au) metal ion complexes with fatty acids (palmitic, oleic, linoleic and α-linolenic) and glycerolipids. Remarkably, the formation of M₂H⁺ ions (M = Cu, Ag) is observed as a dissociation product of the ion complexes containing more than one metal cation and only if the lipid in the complex contains a double bond. Ag₂H⁺ is formed as the main dissociation channel for all three of the fatty acids containing double bonds that were investigated while Cu₂H⁺ is formed with one of the fatty acids and, although abundant, is not the dominant dissociation channel. Also, Cu(I) and Ag(I) ion complexes were observed with glycerolipids (including triacylglycerols and glycerophospholipids) containing either saturated or unsaturated fatty acid substituents. Interestingly, Ag₂H⁺ ion is formed in a major fragmentation channel with the lipids that are able to form the complex with two metal cations (triacylglycerols and glycerophosphoglycerols), while lipids containing a fixed positive charge (glycerophospocholines) complex only with a single metal cation. The formation of Ag₂H⁺ ion is a significant dissociation channel from the complex ion [Ag₂(L–H)]⁺ where L = Glycerophospholipid (GP) (18:1/18:1). Cu(I) also forms complexes of two metal cations with glycerophospholipids but these do not produce Cu₂H⁺ upon dissociation. Rather organic fragments, not containing Cu(I), are formed, perhaps due to different interactions of these metal cations with lipids resulting from the much smaller ionic radius of Cu(I) compared to Ag(I).