Laser photodissociation of the isotopic hydrogen molecular ions. Comparison between experimental and ab initio computed fragment kinetic energy spectra

Under electron ionization conditions, the ortho-substituted Schiff bases N-benzylidene-o-toluidine (1a), N-(o-methylbenzylidene)aniline (1b), N-salicylideneaniline (1c) and N-(o-methoxybenzylidene)aniline (1d) give fragment ions which have been shown by collision-activated mass-analysed ion kinetic energy spectra to have the structure of the protonated molecular ions of indole (2), benzofuran (3), and 1,2-benzisoxazole (4). The molecular ion of N-(o-methylbenzylidene)-o-toluidine (1f) gives as fragment ions not only the protonated molecular ion (2) of indole and the tropylium ion but also the molecular ion of anthracene. Attempts to find supporting evidence for a mechanism for this rearrangement by deuterium labelling of a methyl group in (1b), such as (1g), have been unsuccessful.

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Distributions of the Initial Fragment Kinetic Energy in Binary and Ternary Fission

Canadian Journal of Physics ◽

10.1139/p71-336 ◽

1971 ◽

Vol 49 (22) ◽

pp. 2778-2784 ◽

Cited By ~ 2

Author(s):

P. B. Vitta

Keyword(s):

Kinetic Energy ◽

Translational Motion ◽

Nuclear Fission ◽

Binary Fission ◽

Energy Spectra ◽

Initial Kinetic Energy ◽

Ternary Fission ◽

Internal Excitation ◽

Initial Excitation ◽

Fragment Kinetic Energy

The statistical theory of nuclear fission was originally developed to deal with binary fission. An attempt is made to extend the theory to the case of ternary fission. The probability of a fission mode, given that the nucleus divides into three fragments, is first calculated. Attention is thereafter focused only on the probability distribution of fission modes representing the various possible allocations to the fragment translational motion and internal excitation of the energy available for both translation and excitation. This leads to ternary-fission distributions of the initial kinetic energy (and to complementary distributions of the initial excitation energy) of the fissioning nucleus. Our results show that the ternary-fission distributions of the initial kinetic energy are wider with peaks at higher values of kinetic energy than the corresponding binary-fission distributions obtained previously. The (spontaneous-) ternary-fission distributions are peaked at energies of the order of 1 MeV and have full-widths-at-half-maximum (FWHM) in the neighborhood of 3 MeV. These figures are of experimental interest, since they may be used to predict the energy spectra of the fission fragments in ternary fission.

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Temperatures of fragment kinetic energy spectra

Physical Review C ◽

10.1103/physrevc.51.803 ◽

1995 ◽

Vol 51 (2) ◽

pp. 803-805 ◽

Cited By ~ 39

Author(s):

Wolfgang Bauer

Keyword(s):

Kinetic Energy ◽

Energy Spectra ◽

Fragment Kinetic Energy

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Kinetic energy spectra of divergent wind in the atmosphere

Tellus ◽

10.3402/tellusa.v33i1.10698 ◽

1981 ◽

Vol 33 (1) ◽

pp. 102-104 ◽

Cited By ~ 3

Author(s):

Tsing-Chang Chen ◽

Joseph J. Tribbia

Keyword(s):

Kinetic Energy ◽

Energy Spectra ◽

Divergent Wind

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Rotational de-excitations of C3H+ (1Σ+) by collision with He: new ab initio potential energy surface and scattering calculations

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1086 ◽

2020 ◽

Vol 494 (4) ◽

pp. 5675-5681 ◽

Cited By ~ 1

Author(s):

Sanchit Chhabra ◽

T J Dhilip Kumar

Keyword(s):

Potential Energy ◽

Potential Energy Surface ◽

Ab Initio ◽

Cross Sections ◽

Energy Surface ◽

Molecular Ions ◽

Basis Set ◽

Rate Coefficients ◽

Close Coupling ◽

Collisional Rate Coefficients

ABSTRACT Molecular ions play an important role in the astrochemistry of interstellar and circumstellar media. C3H+ has been identified in the interstellar medium recently. A new potential energy surface of the C3H+–He van der Waals complex is computed using the ab initio explicitly correlated coupled cluster with the single, double and perturbative triple excitation [CCSD(T)-F12] method and the augmented correlation consistent polarized valence triple zeta (aug-cc-pVTZ) basis set. The potential presents a well of 174.6 cm−1 in linear geometry towards the H end. Calculations of pure rotational excitation cross-sections of C3H+ by He are carried out using the exact quantum mechanical close-coupling approach. Cross-sections for transitions among the rotational levels of C3H+ are computed for energies up to 600 cm−1. The cross-sections are used to obtain the collisional rate coefficients for temperatures T ≤ 100 K. Along with laboratory experiments, the results obtained in this work may be very useful for astrophysical applications to understand hydrocarbon chemistry.

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Kinetic energy distributions of secondary molecular ions from thin organic films under ion bombardment

Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms ◽

10.1016/0168-583x(95)01563-9 ◽

1996 ◽

Vol 115 (1-4) ◽

pp. 246-250 ◽

Cited By ~ 25

Author(s):

A. Delcorte ◽

P. Bertrand

Keyword(s):

Kinetic Energy ◽

Ion Bombardment ◽

Molecular Ions ◽

Organic Films ◽

Energy Distributions ◽

Thin Organic Films ◽

Kinetic Energy Distributions

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Sputtering of Neutral Molecules and Molecular Ions From the Adenine Crystal Surface Induced by the UV Picosecond Laser Pulse

Laser Chemistry ◽

10.1155/lc.1.37 ◽

1982 ◽

Vol 1 (1) ◽

pp. 37-43 ◽

Cited By ~ 19

Author(s):

V. S. Antonov ◽

V. S. Letokhov ◽

Yu. A. Matveyets ◽

A. N. Shibanov

Keyword(s):

Laser Radiation ◽

Kinetic Energy ◽

Crystal Surface ◽

Picosecond Laser ◽

Laser Pulses ◽

Molecular Ions ◽

Laser Radiation Intensity ◽

Ion Sputtering ◽

Absorbed Energy ◽

Picosecond Laser Pulse

This paper presents the results of observation of sputtering of neutral molecules and ions from the crystal adenine surface induced by fourth-harmonic Nd:YAG laser radiation with a pulse duration of 30 ps. The energy fluence of laser pulses was in the region (1–3) × 10−4 J/cm2. The kinetic energy distribution of the sputtered molecules spreads up to 0.7 eV. The experiment shows that the threshold of adenine molecular ion sputtering is connected with absorbed energy density in upper layers of the crystal surface but not by laser radiation intensity.

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VUV FRAGMENTATION OF SOME HYDROFLUOROCARBON CATIONS STUDIED USING COINCIDENCE TECHNIQUES

Surface Review and Letters ◽

10.1142/s0218625x0200204x ◽

2002 ◽

Vol 09 (01) ◽

pp. 153-158 ◽

Cited By ~ 5

Author(s):

WEIDONG ZHOU ◽

D. P. SECCOMBE ◽

R. Y. L. CHIM ◽

R. P. TUCKETT

Keyword(s):

Kinetic Energy ◽

Ab Initio ◽

Ground State ◽

Lower Energy ◽

Lone Pair ◽

Electronic States ◽

Photoelectron Spectra ◽

Highest Occupied Molecular Orbital ◽

Impulsive Model ◽

Lone Pair Electrons

Threshold photoelectron–photoion coincidence (TPEPICO) spectroscopy has been used to investigate the decay dynamics of the valence electronic states of the parent cation of several hydrofluorocarbons (HFC), based on fluorine-substituted ethane, in the energy range 11–25 eV. We present data for CF 3– CHF 2, CF 3– CH 2 F , CF 3– CH 3 and CHF 2– CH 3. The threshold photoelectron spectra (TPES) of these molecules show a common feature of a broad, relatively weak ground state, associated with electron removal from the highest-occupied molecular orbital (HOMO) having mainly C–C σ-bonding character. Adiabatic and vertical ionisation energies for the HOMO of the four HFCs are presented, together with corresponding values from ab initio calculations. For those lower-energy molecular orbitals associated with non-bonding fluorine 2pπ lone pair electrons, these electronic states of the HFC cation decay impulsively by C–F bond fission with considerable release of translational kinetic energy. Appearance energies are presented for formation of the daughter cation formed by such a process (e.g. CF 3– CHF +), together with ab initio energies of the corresponding dissociation channel (e.g. CF 3– CHF + + F ). Values for the translational kinetic energy released are compared with the predictions of a pure-impulsive model.

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