Download or read book Quantum State Selected Ion Molecule Reaction Dynamics Studies by Vacuum Ultraviolet Laser and Pulsed Field Ionization photoion Method written by Bo Xiong and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum state resolved pulsed field ionization-photoion (PFI-PI) spectra of several small molecules have been obtained, and a few state-selected and kinetic energy selected ion molecule reactions have been studied in detail in this dissertation. Tunable vacuum ultraviolet (VUV) laser is employed, along with a PFI-PI double-quadrupole double-octupole (DQDO) mass spectrometer to conduct these spectroscopic and chemical dynamics studies. Electronic, vibrational, and rotational selected ions are produced by direct photoexcitation with intense, high-resolution VUV laser to high-n Rydberg states, then field ionized by external pulsed electric fields. Pulsed electric field sequences, including their intensity and duration, are adjusted for each unique molecular ion studied to achieve ion beam kinetic energy resolution of as good as 0.05 eV in the lab frame (E[subscript lab]). Kinetic energy dependent integral cross section measurements are measured in the center-of-mass kinetic energy (E[subscript CM]) range of 0.05 – 10.0 eV. Octupole ion guides are used to transmit reactant and product ions from the source to the mass spectrometer with high transmission efficiency. Quadrupole mass spectrometer is used to selectively transmit ions with specific mass to charge ratio. It is demonstrated a wide range of molecular species can be studied in the present VUV-PFI-PI-DQDO apparatus. In this dissertation, N2+, CH4+, O2+, H2+, H2O+, as well as a transition metal ion V+ are investigated spectroscopically and kinetically. Some quantum state resolved photoions are produced for the first time (e.g. rotational selected H2+, electronically and vibrational selected O2+, and spin-orbit state selected V+). Ion-molecule reactions involving these molecular ions are studied and quantum state effects on their reactivity are noticed and discussed. These include the vibrational state and kinetic energy dependence of the product channels and cross sections of reaction N2+(X2[sigma][subscript g], v+=0-2) + C2H2, the rotational enhancement and more complicated vibrational effects of reaction H2O+(X2B1, v1+v2+v3+, N+[subscript Ka+Kc+]) +HD, the distinctive charge transfer cross sections of O2+(a4[pi][subscript u], X2[pi][subscript g], v+)+Ar with reactant ions in two different electronic states while close in total internal energy, and the vibrational and rotational enhancement of proton transfer reaction of H2+(X2[sigma][subscript g]+, v+=1-3, N+=0-3)+Ne. For the CH4/CH4+ system, it is also shown that through studying the unimolecular dissociation dynamics by the PFI-PI method, thermochemistry data, e.g. appearance energy (AE) and bond dissociation energy (D0), can be obtained with unprecedented accuracy.

Download or read book The Study of State Selected Ion Molecule Reactions Using the Vacuum Ultraviolet Pulsed Field Ionization Photoion Technique written by and published by . This book was released on 2006 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents the methodology to generate beams of ions in single quantum states for bimolecular ion-molecule reaction dynamics studies using pulsed field ionization (PFI) of atoms or molecules in high-n Rydberg states produced by vacuum ultraviolet (VUV) synchrotron or laser photoexcitation. Employing the pseudocontinuum high-resolution VUV synchrotron radiation at the Advanced Light Source as the photoionization source, PFI photoions (PFI-PIs) in selected rovibrational states have been generated for ion-molecule reaction studies using a fast-ion gate to pass the PFI-PIs at a fixed delay with respect to the detection of the PFI photoelectrons (PFI-PEs). The fast ion gate provided by a novel interleaved comb wire gate lens is the key for achieving the optimal signal-to-noise ratio in state-selected ion-molecule collision studies using the VUV synchrotron based PFI-PE secondary ion coincidence (PFI-PESICO) method. The most recent development of the VUV laser PFI-PI scheme for state-selected ion-molecule collision studies is also described. Absolute integral cross sections for state-selected H+2 ions ranging from v+=0 to 17 in collisions with Ar, Ne, and He at controlled translational energies have been obtained by employing the VUV synchrotron based PFI-PESICO scheme.

Download or read book Rovibrationally Selected Ion molecule Reaction Studies Using the Vacuum Ultraviolet Laser Pulsed Field Ionization photoion and Guided Ion Beam Methods written by Yuntao Xu and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have successfully performed rovibrationally selected ion-molecule studies with translational energy in the center-of-mass (E(cm)) from thermal to 10 eV by implementing the Vacuum ultraviolet (VUV) laser-based pulsed field ionization-photoion (PFI-PI) experimental technique with the newly developed double quadrupole-double octopole (DQDO) apparatus in our laboratory. A novel electric pulsing sequence has been developed to prepare ions of interests in single rovibrational states with not only with high intensity but also high translational energy resolution. An unprecedented translational energy resolution as low as 0.05 eV in the laboratory frame ([Delta]E(lab)) is achieved that allows us to investigate the effect rotational, vibrational and translational energy on the chemical reactivity of ion-molecule reactions. Using VUV-PFI-PI technique we show that N2+ ions can be selected in v+ vibrational states from v+ = 0-2 and in a particular N+ rotational levels from N+ = 0-9 at ground electronic state. Similarly, the triatomic H2O+ ions can be prepared in the v1+v2+v3+ = 000, 100 and 020 states and the N+(Ka+Kc+) = 000, 111, and 211 states, respectively, for rovibrationally selected ion-molecule reaction studies. Absolute integral cross sections ([delta]), as well as branching ratios, as a function of both internal ro-vibrational and translational energies of ions, are obtained for the ion-molecule reactions of N2+(X2[Sigma](g)+ ; v+ = 0-2; N+ = 0-9) + Ar/CH4 and H2O+(X2B1 ; v1+v2+v3+= 000; N+(Ka+Kc+)) + D2/CO. Many fascinating phenomena about chemical reaction dynamics are observed for the first time. These include vibrational enhancements in the charge-transfer cross sections of N2+(X2[Sigma]g+; v+; N+) + Ar [arrow right] Ar+ + N2, rotational enhancements in the chemical reactivity of H2O+(X2B1; v1+v2+v3+; N+(Ka+Kc+)) + D2 [arrow right]H2DO+ + D, and distinct activation thresholds in the reaction of H2O+(X2B1; v1+v2+v3+; N+(Ka+Kc+)) + CO [arrow right] CO+ + H2O. This kind of data is unique and it provides a database that serves as benchmarks for theoretical calculations and the modeling of related reaction systems.

Download or read book Advances in Chemical Physics Volume 70 Part 1 written by Ilya Prigogine and published by Wiley-Interscience. This book was released on 1988-01-18 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series serves as the perfect supplement to any advanced graduate class devoted to the study of chemical physics.

Download or read book Mass Analyzed Threshold Ionization photoion with VUV Laser Pulsed Field Ionization and Guided Ion Beam Method Applied to the Study of State selected Ion molecule Reaction Dynamics written by Hong Xu and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation covers four major chapters. In Chapter 1, a general introduction is given on the research methods of state-selected ion-molecule reaction dynamics including VUV generation, pulse field ionization, guided ion beam method, as well as mass analyzed threshold ionization (MATI). Chapter 2 presents the development of instruments construction for the study of state-selected ion-molecule reaction dynamics. Chapter 3 represents a VUV pulsed field ionization-photoelectron spectroscopic study of pyrazine (C6H4N2). The ionization energy was determined to be 74,906.6 ± 2.0 cm−1 (9.28728 ± 0.00025 eV). The PFI-PE spectrum of pyrazine exhibits well-resolved vibrational bands, which have been well characterized. In Chapter 4 the first rotationally resolved mass-analyzed-threshold (MATI) photoion spectra of N2(X2 [sigma][subscript g], v=0, 1) bands of nitrogen is reported with high resolution using the pulsed field ionization method. The rovibrational spectrum of N2+(X2 [sigma]+[subscript g], v+=0, 1) is analyzed. Absolute rovibrationally selected total cross sections for the charge transfer reaction N2+(X2 [sigma]+[subscript g], v+=0, 1) + Ar are measured.

Download or read book Advances in Chemical Physics State Selected and State to State Ion Molecule Reaction Dynamics written by Michael Baer and published by Wiley-Interscience. This book was released on 2009-09-08 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book State Selected Ion Molecule Reaction Dynamics written by R. J. S. Morrison and published by . This book was released on 1984 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: By analyzing the photoelectron energies in several systems, it has been demonstrated that multiphoton ionization (MPI) can selectively produce molecular ions predominantly in a single vibrational level by the proper choice of the laser wavelength employed. Thus MPI provides a powerful new technique for producing high densities of internally state-selected reagent ion for chemical reaction dynamics studies. This approach is being taken for studying the ion-molecule reactions of NH3(+) (v) which has been prepared with v = 0-9 vibrational quanta in the nu sub 2 umbrella-bending mode.

Download or read book Unimolecular and Bimolecular Ion Molecule Reaction Dynamics written by Cheuk-Yiu Ng and published by . This book was released on 1994-09-06 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unimolecular and Bimolecular Ion—Molecule Reaction Dynamics Cheuk-Yiu Ng, Ames Laboratory, Iowa State University, Iowa, USA Tomas Baer, University of North Carolina, NC, USA Ivan Powis, University of Nottingham, UK Recent advances in both experimental techniques and theoretical methodologies have meant that increasingly sophisticated studies concerning the formation, structures, energetics, and reaction dynamics of state- or energy-selected molecular ions can now be performed. In order to better serve the ion chemistry and physics community, each volume of this series will be dedicated to reviewing a specific topic, emphasizing new experimental and theoretical developments in the study of ions. This third volume is devoted to the study of unimolecular and bimolecular ionic processes. Special emphasis is given to studies related to planetary and interstellar ion chemistry and physics, the understanding of which has been a great impetus to the study of ion—molecule reactions. Each of the nine chapters making up this volume is written by a leading researcher in the respective field. This series will help stimulate new research directions and point to future opportunities in the fields of ion chemistry and physics.

Download or read book State Selected and State to State Ion Molecule Reaction Dynamics Volume 82 2 Part Set written by Ilya Prigogine and published by Wiley-Interscience. This book was released on 1993-02-08 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series serves as the perfect supplement to any advanced graduate class devoted to the study of chemical physics.

Download or read book Energy Research Abstracts written by and published by . This book was released on 1988 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Chemical Physics State Selected and State to State Ion Molecule Reaction Dynamics written by Michael Baer and published by Wiley-Interscience. This book was released on 1992-02-11 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ultrafast Chemical Dynamics of Atoms and Molecules Studied by Femtosecond Time resolved Extreme Ultraviolet Transient Absorption Spectroscopy written by Ming-Fu Lin and published by . This book was released on 2013 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultrafast femtosecond (10−15 s) dynamics of atomic xenon, vinyl bromide and carbon disulfide molecules are studied using a newly developed method of extreme ultraviolet (XUV) transient absorption spectroscopy. This research work is devoted to a deeper understanding of the fundamental electronic and nuclear dynamics using XUV light pulses from a high-order harmonic generation source. The produced XUV light pulses are utilized to selectively probe the chemical reaction coordinate with femtosecond temporal resolution. The experimental apparatus for transient absorption pump-probe spectroscopy is described in detail. The research described in this thesis contains four different gaseous atomic and molecular systems. The first system in the study is motivated by a goal to gain a better understanding of the core-excited state couplings of atomic xenon near zero delay between an intense NIR pump pulse (780 nm) and an XUV probe pulse. Secondly, the ionization and dissociation dynamics of molecular vinyl bromide (C2H3Br) under the influence of strong-field ionization are investigated. Finally, an ongoing research project of CS2 and thiophene molecules is presented for future studies of spin-orbit wavepacket and ring-opening dynamics, respectively. The NIR induced core-excited state coupling of atomic xenon is studied using femtosecond XUV transient absorption spectroscopy with photon energies between 50 eV to 70 eV. Coupling of the core-excited states 4d−1(2D5/2)6p(2P3/2) (65.1 eV) and 4d−1(2D3/2)6p(2P1/2) (67.0 eV) to neighboring states by the NIR field results in a threefold enhancement of XUV transmission. The induced transmission at 65.1 eV (67.0 eV) changes from 3.2 ± 0.4% (5.9 ± 0.5%) without the coupling laser to 9 ± 2% (22 ± 5%) at the maximum of the NIR field. A NIR field induced broad XUV absorption feature ranging from 60 eV to 65 eV is explained by the splitting of the field free absorption lines into multiplets when the Rabi frequencies of the coupling transitions higher than the NIR frequency. This assignment is supported by a numerical integration of the von Neumann equation for a few level quantum system. The dissociative ionization dynamics of vinyl bromide, C2H3Br, initiated by a strong laser field ionization are investigated. XUV light pulses with photon energy between 50 eV and 72 eV are utilized to detect the subsequent dynamics. Several dynamic features are observed including the neutral C2H3Br depletion, the formation of C2H3Br ions (X and A states), the production of C2H3Br dications, and the emergence of neutral Br (2P3/2) atoms from dissociative ionization. Free Br (2P3/2) atoms appear on a timescale of 330±150 fs. The singly charged ionic A state displays a time-dependent XUV absorption energy shift of ~0.4 eV during the first 300 fs after strong-filed ionization. The signal intensity from Br atoms correlates with the signal intensity from singly charged parent ions in the A state as a function of NIR laser peak intensity. The experimental observations suggest that vibrationally excited C2H3Br+ (A) ions possibly undergo ultrafast intramolecular vibrational energy redistribution concurrent with the C-Br bond dissociation within a time scale of 330±150 fs. The C2H3Br+ (X) and C2H3Br++ ions are relatively stable as a consequence of deeper potential wells and a high dissociation barrier, respectively. Two ongoing experiments of sulfur-containing molecules are presented that are aimed at future studies of a molecular spin-orbit wavepacket in CS2+ ions and ultrafast ring-opening dynamics of thiophene. Strong-field ionization can coherently populate two spin-orbit states in CS2+ ions. The spin-orbit splitting originates from the atomic sulfur (~60 meV). The small splitting offers the possibility to probe a coherent beating on a time scale of 69 fs, well beyond our temporal resolution of 25 fs. For thiophene, an ultrafast ring-opening process initiated by one-photon excitation at 193 nm is studied through multiphoton ionization at 780 nm. The parent ion population exhibits a fast decay on a time scale of 200±30 fs. This offers a reference for the future XUV transient absorption experiments using one-photon excitation at 193 nm and sulfur (2p) L-edge detection at 165 eV.

Download or read book State selected and State to state Ion molecule Reaction Dynamics written by Cheuk-Yiu Ng and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book State Selected and State to State Ion Molecule Reaction Dynamics Volume 82 Part 2 written by Michael Baer and published by Wiley-Interscience. This book was released on 1992-04-16 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series serves as the perfect supplement to any advanced graduate class devoted to the study of chemical physics.

Download or read book Photoelectron Ion Correlation in Photoionization of a Hydrogen Molecule and Molecule Photon Dynamics in a Cavity written by Takanori Nishi and published by Springer Nature. This book was released on 2022-05-03 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the latest theoretical studies giving new predictions and interpretations on the quantum correlation in molecular dynamics induced by ultrashort laser pulses. The author quantifies the amount of correlation in terms of entanglement by employing methods developed in quantum information science, in particular applied to the photoionization of a hydrogen molecule. It is also revealed that the photoelectron–ion correlation affects the vibrational dynamics of the molecular ion and induces the attosecond-level time delay in the molecular vibration. Furthermore, the book also presents how molecular vibration can couple to photons in a plasmoic nanocavity. Physicists and chemists interested in the ultrafast molecular dynamics would be the most relevant readers. They can learn how we can employ the quantum-information-science tools to understand the correlation in the molecular dynamics and why we should consider the correlation between the photoelectron and the molecular ion to describe the ion’s dynamics. They can also learn how to treat a molecule coupled to photons in a nanocavity. All the topics are related to the state-of-the-art experiments, and so, it is important to publish these results to enhance the understanding and to induce new experiments to confirm the theory presented.

Download or read book Electronic and nuclear quantum dynamics of molecules in intense laser fields written by Yuichi Fujimura and published by Frontiers Media SA. This book was released on 2023-04-28 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Imaging in Chemical Dynamics written by Arthur G. Suits and published by . This book was released on 2001 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive review of the rapidly growing field of imaging-based probes of chemical dynamics. It includes discussions of state-resolved photodissociation dynamics, orbital alignment and vector correlations, radical photodissociation, surface scattering, imaging photoelectron spectroscopy, ultrafast dynamics and coincidence techniques.