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Carbon dioxide (CO2) was used as a reaction gas to investigate the gas‐phase ion‐molecule interactions using the Agilent 8900 ICP‐MS/MS. A solution containing forty‐five elements representative of the periodic table was used to supply the ions to react with CO2 in the collision/reaction cell (CRC). The only significant product ions formed were monoxides. The general reactivity was shown to be consistent with density functional theory (DFT)‐predicted reaction enthalpies, such that all predicted exothermic reactions produced product ions at levels of at least 1% of the unreacted ion. Most endothermic reactions observed had sufficient kinetic energy in excess of the reaction enthalpies. Our results suggest that reaction enthalpy is a reasonable predictor of reactivity with CO2 on the timescales of the interactions in non‐thermal ICP‐MS/MS systems. The ease and rapidity of data collection with the ICP‐MS/MS and DFT calculations using the NWChem suite has value given the scarcity of thermochemical data of CO2 reactions in the literature. These studies are especially useful for the identification of targeted reaction chemistries to be leveraged for analytical method development, such as for the inline separation of isobaric interferences from analytes of interest. [ABSTRACT FROM AUTHOR]

We report two-color resonant two-photon ionization spectra of internally cold benzyl-h7, benzyl-αd2, and benzyl-d7 radicals in the region of the vibronically mixed A 2A2–B 2B2 excited states near 450 nm. Spectra of the corresponding 1:1 van der Waals complexes benzyl·Ar are reported as well. Band intensities of threshold photoionization spectra using a variety of mixed A 2A2–B 2B2 vibronic states as intermediates provide additional new information about the mechanism of vibronic coupling. A semiquantitative coupling model based on crude adiabatic states attempts to interpret all available data from absorption, dispersed fluorescence, and pulsed field ionization (ZEKE-PFI) spectra. The two b1-symmetry modes ν28 (an in-plane skeletal deformation) and ν21 (an in-plane skeletal plus CCH bending motion) couple the A and B states most strongly. In contrast to earlier interpretations, we find that the b1 combination ν17+ν36 plays a prominent role, while the b1 in-plane–CH2 rock ν29 is unimportant. The dispersed fluorescence work of Selco and Carrick and of Fukushima and Obi shows clear evidence of substantial coupling of the A and C states through the a1 mode ν13, in accord with the semiempirical vibronic coupling calculations of Negri et al. In contrast with those calculations, our model seemingly demands no A–B vibronic coupling matrix elements larger than 100–200 cm-1. Thus the dramatic effects of A–B vibronic coupling result primarily from the near-degeneracy of the two excited states rather than unusually strong vibronic coupling matrix elements. Some fluorescence and PFl band intensities involving ν28 and ν21 deviate substantially from simple predictions based on products of squared mixing coefficients times Franck–Condon factors. A complete understanding of the spectra will require a quantitative account of Duschinsky mixing, which in turn requires accurate... [ABSTRACT FROM AUTHOR]

We have measured threshold photoionization spectra of benzyl+-h7, benzyl+-αd2, and benzyl+-d7 in the ground electronic state (X+ 1A1) using resonant two-photon excitation and detection of electrons by pulsed field ionization. The adiabatic ionization potentials of benzyl-h7, benzyl-αd2, and benzyl-d7 are 58 468±5 cm-1, 58 418±5 cm-1, and 58 386±5 cm-1. Excitation through a variety of vibronically mixed A 2A2–B 2B2 neutral excited states allows observation of cation vibrations of both a1 and b1 symmetries. We directly measure in-plane fundamentals and infer the frequencies of certain out-of-plane fundamentals from their involvement in combinations or overtones. By comparison with harmonic frequencies from ab initio calculations, we assign 35 of 48 observed levels in the -h7 isotopomer, 15 of 22 levels in -αd2, and 25 of 30 levels in -d7. Ab initio calculations permit a detailed comparison of the geometry, chemical bonding, and vibrational frequencies in the benzyl anion, neutral, and cation. The anion and cation, both closed-shell species, have remarkably similar geometries with relatively short exocyclic CC bond (1.371 Å and 1.372 Å, respectively) and with the aromatic ring compressed along the C2 symmetry axis. The neutral free radical has a longer exocyclic CC bond (1.413 Å) and a more nearly sixfold symmetric ring. The natural resonance theory provides bond orders and resonance-structure weights in all three species. While no single resonance structure dominates in any of the three species, the structure with an exocyclic CC double bond is significantly more important in the anion and cation than in the neutral. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We report four vibrational bands from 0–650 cm-1 for benzyl+-h7, benzyl+-αd2, and benzyl+-d7. The exocyclic C—C bond of benzyl cation has substantial double bond character. Band assignments from ab initio frequencies illuminate the mechanism of vibronic coupling in the 1 2A2–2 2B2 system of neutral benzyl. The adiabatic ionization potential of benzyl-h7 is 7.2484±0.0006 eV. [ABSTRACT FROM AUTHOR]

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