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In this paper, we investigated the stickiness effect of the Hamilton system of the Hydrogen atom exposed to intense laser field. Even for the one electron system, its Poincare surface of section shows the chaotic and regular parts due to the laser field which can be explained by KAM (Kolmogorov, Arnold, and Moser) theory. The unstable periodic orbit (UPO) in chaotic "sea" was located by variational method and the corresponding stable manifold (SM) and unstable manifold (UM) of the UPO were numerically calculated. It was shown that the dynamics of ionization of the one electron system is governed by the UPO. On one hand, the SM of UPO is well superposed with the recurrence plot, which indicates that the SM overlaps just the stable initial points in phase space. On the other hand, the UM is almost coincide with the densely distributed points on Poincare surface of section. This indicated that the UM is just the ionization channels of the trajectories driven by laser field. Furthermore, the survival probabilities of different regions which gradually cross the UM and SM tangential flow nearby the stable island are studied. They obey an algebraic decaying law. The similar decay trend are also observed on different regions on the UM which possess almost the same decay parameters with that of region nearby the UPO. These observations confirmed that the stability properties of UPO play very important role in the stickiness effect of the phase space nearby the KAM stable islands. [ABSTRACT FROM AUTHOR]

Comprehensive two‐dimensional gas chromatography (GC × GC) coupled to time‐of‐flight mass spectrometry is a powerful separation tool for complex petroleum product analysis. However, the most commonly used electron ionization (EI) technique often makes the identification of the majority of hydrocarbons impossible due to the exhaustive fragmentation and lack of molecular ion preservation, prompting the need of soft‐ionization energies. In this study, three different soft‐ionization techniques including photo ionization (PI), chemical ionization (CI), and field ionization (FI) were compared against EI to elucidate their relative capabilities to reveal different base oil hydrocarbon classes. Compared with EI (70 eV), PI (10.8 eV) retained significant molecular ion (M+·) information for a large number of isomeric species including branched‐alkanes and saturated monocyclic hydrocarbons along with unique fragmentation patterns. However, for bicyclic/polycyclic naphthenic and aromatic compounds, EI played upper hand by retaining molecular as well as fragment ions to identify the species, whereas PI exhibited mainly molecular ion signals. On the other hand, CI revealed selectivity towards different base oil groups, particularly for steranes, sulfur‐containing thiophenes, and esters, yielding protonated molecular ions (M + H)+ for unsaturated and hydride abstracted ions (M‐H+) for saturated hydrocarbons. FI, as expected, generated intact molecular ions (M+·) irrespective to the base oil chemical classes. It allowed elemental composition by TOFMS with a mass resolving power up to 8000 (FWHM) and a mass accuracy of 1 mDa, leading to the calculation of heteroatomic content, double bond equivalency, and carbon number of the compounds. The qualitative and quantitative results presented herein offer a unique perspective into the detailed comparison of different ionization techniques corresponding to several hydrocarbon classes. [ABSTRACT FROM AUTHOR]

Highlights • Design of PID sensor with compositional output for the test sample. • Successfully discriminate between very low concentrations of VOC samples. • Detectable concentration down to 2 ppm isobutylene. • Leak proof sensor design. Abstract We report on the design, fabrication and verification of a portable, low cost PID. Unlike commercial PID sensors, ours provides two outputs. One output correlates to the total chemical components and a second that provides some level of compositional information. We believe that this makes this sensor system more useful than a standard commercial PID, at a similar cost point. Our PID sensor was tested with gas concentrations down to 2 ppm isobutylene. The results presented indicate that the limit of detection will be well below 1 ppm. Compositional analysis was also carried out and the results presented shows our sensor can successfully discriminate between low concentrations of 2-hexanone, isobutylene, propanol, 2-pentanone, 2-octanone and 2-heptanone. [ABSTRACT FROM AUTHOR]

A low cost portable photoionization (PID) sensor was successfully designed and manufactured. Unlike existing commercial PID sensors, our device provides two outputs, one associated with the total chemical components and a second that provides some level of compositional information. We believe that this makes this sensor system more useful than a standard PID, with a similar, if not lower, cost point. Our PID sensor was tested with gas concentrations down to 2 ppm isobutylene. These results indicate that the limit of detection will be well below 1 ppm. Further detection tests were carried out with ethanol, acetone and isobutylene, which showed similar sensitivities. Compositional measurements were also undertaken and the results presented shows our sensor can discriminate successfully between low concentration isobutylene and 2-pentanone.

Highlights: [•] First time M sub shell fluorescence cross section measurements at 8 and 10keV photons. [•] Comparison with theoretical evaluations from different model data for parameters. [•] Explained the large deviations from the trend of parameters with atomic number Z. [•] A specific pattern of cross sections with Z is predicted in the region, 78⩽ Z ⩽92. [•] Confirmation of prediction requires more experiment in these Z and energy region. [Copyright &y& Elsevier]

Highlights: [•] We have examined the basic principle of analysis with PID detector. [•] We have correlated the PID detector signal with SPA analysis result. [•] We have examined the ability of the PID detector for analyzing the tar during gasification. [ABSTRACT FROM AUTHOR]

Abstract: A microprobe sampling device (μ-probe) has been developed for in situ on-line photo ionization mass spectrometric analysis of volatile chemical species formed within objects consisting of organic matter during thermal processing. With this approach the chemical signature occurring during heating, pyrolysis, combustion, roasting and charring of organic material within burning objects such as burning fuel particles (e.g., biomass or coal pieces), lit cigarettes or thermally processed food products (e.g., roasting of coffee beans) can be investigated. Due to its dynamic changes between combustion and pyrolysis phases the cigarette smoking process is particularly interesting and has been chosen as first application. For this investigation the tip of the μ-probe is inserted directly into the tobacco rod and volatile organic compounds from inside the burning cigarette are extracted and real-time analyzed as the glowing front (or coal) approaches and passes the μ-probe sampling position. The combination of micro-sampling with photo ionization time-of-flight mass spectrometry (PI-TOFMS) allows on-line intrapuff-resolved analysis of species formation inside a burning cigarette. Monitoring volatile smoke compounds during cigarette puffing and smoldering cycles in this way provides unparalleled insights into formation mechanisms and their time-dependent change. Using this technique the changes from pyrolysis conditions to combustion conditions inside the coal of a cigarette could be observed directly. A comparative analysis of species formation within a burning Kentucky 2R4F reference cigarette with μ-probe analysis reveals different patterns and behaviors for nicotine, and a range of semi-volatile aromatic and aliphatic species. [Copyright &y& Elsevier]

A newly developed measurement technique for evolved gas analysis in thermogravimetry, viz. a thermo balance coupled to comprehensive gas chromatography/single photon ionization mass spectrometry (TG-GC × SPIMS), has been applied to investigate the thermal degradation of two polymers (polycarbonate (PC) blended with ABS and PVC). This detection method provides a two-dimensional analysis of the evolved gaseous products. TG relevant data is obtained as well as an improved resolution power to separate isobaric molecular structures without losing any fraction of the samples. In addition, this solution is not associated with any extension of the measurement time. The assignment of the substance pattern to distinct species is improved compared to solely using MS without a preceding separation step. Furthermore, hitherto undetected compounds when compared to applying TG-SPIMS without GC such as benzonitrile and its methylated derivatives have been found in the evolved gases from the thermal degradation of PC/ABS blend. Finally, a first estimation of the limit of detection has been carried out, yielding 400 ppt for styrene and 500 ppt for toluene from the thermal decomposition of PC/ABS blend. [ABSTRACT FROM AUTHOR]

Abstract: Soft laser photo-ionization mass spectroemtry is presented as a separation dimension hyphenated with gas chromatographic techniques. Single photon ionization (SPI) is a universal soft ionization method which ionizes organic molecules with an ionization potential below 10.5eV if 118nm laser radiation is used. The inherently soft ionization of photo ionization techniques can further be utilized together with gas chromatography as a comprehensive two-dimensional separation method (GC×MS), using the GC retention time as first separation dimension and the molecular mass as second separation dimension. Some GC×MS chromatograms of diesel petroleum samples using SPI are presented and discussed. Finally, it is demonstrated that the coupling of soft SPI mass spectrometry with comprehensive two-dimensional gas chromatography (GC×GC) provides a three-dimensional separation technique (GC×GC×SPI-MS). [Copyright &y& Elsevier]

Abstract: This paper presents work in progress for development of an on-line method based on PID (Photo Ionization Detector) for quantitative measurement of tar from biomass gasification. To calibrate the method the PID signals are compared to quantitative data of individual tar compounds obtained by an established reference method. The measured response factors for the model tar compounds demonstrated very good linearity. The PID approach was tested on-line with real producer gases from an atmospheric fluidized bed gasifier operated at 800–900°C. The results suggest that PID can be used for continuous on-line tar measurement of product gases from biomass gasification. [Copyright &y& Elsevier]

• Pyrolysis-gas chromatography- high resolution mass spectrometry was useful for insoluble polymers. • Structural analysis of polymer semiconductor poly(3-hexylthiophene) was performed. • Integrating mass spectra in wide time range to one mass spectrum lead to efficient analysis. • The integrated mass spectrum could be analyzed by Kendrick mass defect analysis. • Direct injection of pyrolyzed products into mass spectrometer reduced measurement time. Structural analysis of polymer semiconductors is important to improve their properties but applicable method is limited due to insolubility. Here an efficient and comprehensive data mining method for such materials is developed by using pyrolysis-gas chromatography- high resolution mass spectrometry (Py-GC-HRMS). Py-GC-HRMS analysis of a polymer semiconductor poly(3-hexylthiophene) (P3HT) was performed and pyrogram with vast number of peaks was obtained. Normally in analysis of Py-GC-HRMS results, a mass spectrum is obtained for one peak in chromatogram. In one of our techniques, the mass spectra in wide time range were integrated to one mass spectrum including the information of over 300 compounds. Analysis of the mass spectrum could be using Kendrick mass defect (KMD) analysis. By making KMD plots, the compounds categorized into 29 groups depending on the structures of thiophene derivative moieties. As a result, chemical composition analysis for 29 compounds lead to peak assignment for 277 compounds in short time. Furthermore, these compounds could be categorized depending on different structural features (e.g., number of sulfur atoms, degree of unsaturation) by using appropriate divisors, leading to understanding of relationship between structural features of compounds and their retention time. The measurement without GC column provided the similar information about compounds, although the information of the retention time was lost. These methods can be one of key analysis method for insoluble polymer materials. [ABSTRACT FROM AUTHOR]