Quantum Chemistry Study on Structures of Cluster Ions Nb_(n)S_(m)^(±)Generated by Laser Mass Spectra

ccording to the chemical bond theory we designed geometric structures ofcluster ions Nb_nS generated by laser ablation and calculated their electronic struc-tures using DV-X_a method of quantum chemistry. The results show that with theincrease of the cluster size the structures of the cluster ions change from a single-chain to a double-chain, then to a planar-net, and linking up to a net at Nb_3. Thenegative cluster ions tend to form a divergent configuration due to the extra chargeson it.

A STUDY OF DOUBLY CHARGED ION MASS SPECTRA(2E SPECTRA) OF BIPHENYL DERIVATIVES

The 2E spectra and substituent effects and target gas pressure dependence of the 2E spectra of 7 biphenyl derivatives were discussed. The electron-donating groups favour the molecular ions, but the electron withdrawing groups favour the fragaent ions produced by losing the substituents from molecular ions. The variation of target gas pressure affects the TIC,sample ion current,and the ratio of sample ion current to TIC sharply.However it has no effect on the fragmentation pattern.

MASS SPECTRA OF SUBSTITUTED BENZYLGLYOXALS WITH DEUTERIUM EXCHANGE

Mass spectral behavior of some deuterated and non-deuterated substituted benzylglyoxals was characteristic in enolic structure which was also proved by NMR spectrum. Fragmentation of the title compounds in their mass spectra was ressonably explained in this paper.

THE NEGATIVE-ION CHEMICAL-IONIZATION MASS SPECTRA OF SOME 2, 6, 7-TRIOXA-1-PHOSPHABICYCLO[2.2.2]OCTANE-1-OXIDE DERIVATIVES

The metaphosphate anion, PO_3, was detected in the negative-ion chemicalionization mass spectra of 2,6,7-trioxa-1-phospbabicyclo[2.2. 2] octane-1-oxides.

STRUCTURE EFFECTS OF SILICON AND CARBON BY CLUSTER MASS SPECTRA

Microclusters from different structures of silicon and carbon are studied by SIMS under UHV conditions in the mass range below M=200. The sputtered mass spectra of ions Sin+, Cn+ and Cn were obtained from the 10 keV O2+ primary beam bombardment. Comparisons of each spectrum in each group have shown the strong structure effects on the cluster patterns. A brief discussion on the results has been given.

Mass Spectra of Heavy and Light Mesons Using Asymptotic Iteration Method

The non-relativistic radial Schr¨odinger equation is analytically solved using asymptotic iteration method within the framework of a general interaction potential whose special cases are the Cornell and Cornell plus harmonic potentials. The energy eigenvalues expression is derived in three dimensional space, which is further used to calculate the mass spectra of ˉcc,ˉbb,ˉbc, cˉs, bˉs and b ˉq mesons. The obtained results of this work are in good agreement with experimental and other relativistic results and also improved in comparison with other non-relativistic recent studies.

Mass spectra and wave functions of the doubly heavy baryons with J^P=1^+ heavy diquark cores

Mass spectra and wave functions of the doubly heavy baryons are computed assuming that the two heavy quarks inside a baryon form a compact heavy'diquark core'in a color anti-triplet,and bind with the remaining light quark into a colorless baryon.The two reduced two-body problems are described by the relativistic Bethe-Salpeter equations(BSEs)with the relevant QCD inspired kernels.We focus on the doubly heavy baryons with 1^+heavy diquark cores.After solving BSEs in the instantaneous approximation,we present the mass spectra and the relativistic wave functions of the diquark cores,and of the low-lying baryon states J^P=(1/2)^+and(3/2)^+with flavors(ccq)(bcq)and(bbq).A comparison with other approaches is also made.

Mass spectra and decay of mesons under strong external magnetic field

We study the mass spectra and decay process of σ and π_(0) mesons under a strong external magnetic field.To achieve this goal,we deduce the thermodynamic potential in a two-flavor,hot and magnetized Nambu-Jona-Lasinio model.We calculate the energy gap equation through the random phase approximation(RPA).Then we use the Ritus method to calculate the decay triangle diagram and self-energy in the presence of a constant magnetic field B.Our results indicate that the magnetic field has little influence on the mass of π_(0) at low temperatures.However,for quarks andσmesons,their mass clearly changes,which reflects the influence of magnetic catalysis(MC).The presence of a magnetic field accelerates the decay of the meson while the presence of a chemical potential will decrease the decay process.

An Explanation on the Electron Ionization Mass Spectra of Crown Ethers by MNDO Computational Method

he bond lengths and bond orders of four kinds of chemical bonds in crownethers(15) were calculated based on the model molecules using MNDO method.With the calculation results, some predictions to the EI mass spectral fragmenta-tion behaviour of crown ethers are suggested. The EI mass spectra of studied crownethers are in satisfactory agreenient with the predictions.

THE MASS SPECTRA OF AROMATIC CONJUGATED POLYENIC ACID,METHYL BENZOATE,METHYL PHENYL KETONE,BENZONITRILE AND ANILINE AND THEIR QUANTUM CHEMICAL CALCULATIONS

A quantitative interpretation of mass spectra of complex organic compounds so far is notvery perfect and needs some further investigation. In this paper a mechanism of cleft-rate-determining-steps of aromatic conjugated polyenic acid, methyl benzoate, methyl phenyl ketone,benzonitrile and aniline is proposed, and various quantum parameters of molecular ions ofaromatic conjugated polyenic compounds, together with their framents are calculated bymeans of CNDO/2 method. Through the process of calculation, the peak-height of mass spectracan be quantitatively interpreted, which means that the main factors which influence the cleftforms of simple cleavage of mass spectra of conjugated compounds given by the authorsmight be true to some extent.

Characteristics of mass spectra of dichlorocarbene derivatives of isomeric dodecen-1-ols

The m/z of characteristic ion of the mass spectra of the dichlorocarbene of dodecen-1-ols was used as a parameter to locate the position of double bond in these isomers by a new formula.

Mass spectra of organolanthanide complexes

The EI mass spectra of seven 1,1'-(3-oxa-pentamethylene)-dicyclopentadienyl lanthanide and yttrium chlorides(1—7),and eleven dicyclopentadienyl lanthanide and yttrium chlorides(8—18) were investigated.Fragmentation patterns of these complexes were studied by using metastable ion measurements.The EI spectra of complexes 1—7 exhibited strong molecular ion peaks,the frag- mentation of molecular ions were more complicated.The EI mass spectra of complexes 8—18 sup- ported the dimeric structure under gaseous state.In the spectra of dimers(C_5H_5)_3Ln^+·observed were resulted from the skeletal rearrangement involving the migration of cyclopentadienyl moiety.

MASS SPECTRAL STUDIES ON COMPLEXES OF 1-PHENYL-3-METHYL-4-(β-BENZOYLACETYL)-PYRAZOLONE-5 WITH LANTHANUM, EUROPIUM AND TERBIUM

Ⅰ. INTRODUCTION Mass spectra for complexes of β-diketones of rare earth elements have already been studied. But most of them are those in which the rare earth elements coordinate to diketones with fluorated alkanes or heterocyclic rings. The mass spectra for complexes of 1-phenyl-3-methyl-4-(-benzoylacetyl)-pyrazolone-5 with La, Eu or Tb, the synthesis of this ligand and the study on the mass spectra of its RE-complexes are reported for the first time.

Mass Spectrometric Study of Acetylated Glycopyranosyl Azides

Introduction Glycosyl azides are useful, versatile intermediates for the synthesis of N-glyeosyl derivatives and other biologically important non-carbohydrate derivatives since the azido group can be introduced readily into aliphatic, aromatic and heterocyclic systems, and can be transformed into other functional groups and utilized for the synthesis of hetero-

Mass Spectrometric Characterization of a Thermolabile Metabolite of Camazepam

Incubation of camazepam [3-(N,N-dimethyl) carbamoyloxy-7-chloro-1- methyl-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-2-one] with rat liver microsomes and cofactors produced a 3-(N-methyl-N-hydroxymethyl) carbamoyloxy derivative as the most abundant metabolite.This metabolite was thermally unstable and was isolated from a metabolite mixture by normal-phase High-Performance Liquid Chromatography.Its struc- ture was established by chemical ionization and ^(252)Cf plasma desorption time-of-flight mass spectral analyses.

FAB MASS SPECTROMETRY OF THE PHENOLATEBRIDGED N_8O_3 SCHIFFBASE CRYPTANDS

The fast atom bobardment mass spectra of phenolate-bridged N8O3 Schiff-2base cryptands derived from tris （2-aminoethyl） amine （tren） with 2, 6-dlformyl-4-R-phenol （Cryptand H3L1, R=OMe） H3L3, Br, and H3L4, Ph) in the presence of NaOH or KON in methanol at ambient temperature was investigaed and compared with IR, UV-Vis, 1H and 13H NMR. The characteristic spectra of the cryptates posseessing different proton form cryptands were discussed.

Study of Non-Thermal DC Arc Plasma of CH_4/Ar at Atmospheric Pressure Using Optical Emission Spectroscopy and Mass Spectrometry

Non-thermal C/H/Ar plasmas are widely applied to carbonaceous material production and processing.In this work,plasma parameters and gaseous species of the atmospheric non-thermal C/H/Ar plasmas produced by an atmospheric-pressure DC arc discharge generator in CH_4/Ar were investigated.The voltage-current characteristics were measured for different CH_4/Ar ratios.Optical emission spectroscopy was employed to analyze the electron excitation temperature,gas temperature and electron density under various discharge conditions.The hydrocarbon molecules produced in the CH4/Ar plasmas were detected with photoionization mass spectrometry.The optical spectral results demonstrated that the electron excitation temperature was 0.4-1 eV,the gas temperature was 2800-4200 K and the electron density was in the range of（5-20）×10^15 cm^-3.The mass spectrum indicated that a variety of unsaturated hydrocarbons（C2H4,C3H6,C6H6,etc.） and several highly unsaturated hydrocarbons（C4H2,C5H6,etc.） were produced in the non-thermal arc plasmas.

抗肿瘤药物卡铂的分离和杂质鉴定

本文选择卡铂注射液为样本,对其进行液相色谱质谱分析,旨在解析铂类化合物的色谱行为和质谱特性。在分析过程中,采用了含0.1%甲酸的水-乙腈为流动相,确保在高效液相色谱(HPLC)系统中实现梯度洗脱,进一步在飞行时间质谱(TOF/MS)中以正离子模式对样品进行电离处理。研究结果显示,卡铂分子及其相关物质在XDB-C18色谱柱上实现了良好的分离,减少了铂类化合物的定性分析过程中的干扰,且TOF/MS谱图上呈现出卡铂分子的同位素特征峰。此外,还对卡铂分子的质谱裂解途径进行了归纳总结,为理解其质谱行为提供了有价值的见解。综上所述,本研究所采用的分析方法不仅简便快捷,而且精准可靠,为铂类化合物的定性定量分析提供了一定的参考。

Analysis of GC×GC fingerprints from medicinal materials using a novel contour detection algorithm:A case of Curcuma wenyujin

This study introduces an innovative contour detection algorithm,PeakCET,designed for rapid and efficient analysis of natural product image fingerprints using comprehensive two-dimensional gas chromatogram(GC×GC).This method innovatively combines contour edge tracking with affinity propagation(AP)clustering for peak detection in GC×GC fingerprints,the first in this field.Contour edge tracking signif-icantly reduces false positives caused by“burr”signals,while AP clustering enhances detection accuracy in the face of false negatives.The efficacy of this approach is demonstrated using three medicinal products derived from Curcuma wenyujin.PeakCET not only performs contour detection but also employs inter-group peak matching and peak-volume percentage calculations to assess the compositional similarities and differences among various samples.Furthermore,this algorithm compares the GC×GC fingerprints of Radix/Rhizoma Curcumae Wenyujin with those of products from different botanical origins.The findings reveal that genetic and geographical factors influence the accumulation of secondary metabolites in various plant tissues.Each sample exhibits unique characteristic components alongside common ones,and vari-ations in content may influence their therapeutic effectiveness.This research establishes a foundational data-set for the quality assessment of Curcuma products and paves the way for the application of computer vision techniques in two-dimensional(2D)fingerprint analysis of GC×GC data.

Plasma Immersion Ion Implantation of the Pea Seed and Its RBS Spectra

Plasma immersion ion implantation (PI^3), a new technique with certain advantages over biological samples, was developed. Argonion as well as nitrogen ion implantation of the pea seeds has been carried out with the PI^3 implanter and their RBS spectra were also studied. The results show that the mass deposition effect of ion implantation on biological samples can be achieved with the PI^3 implanter. In addition, there is an optimal implantation time for a given treatment condition. It presents new possibilities for the ion implantation into biological samples.