Ionization Thresholds of Small Carbon Clusters:  Tunable VUV Experiments and Theory

Belau, Leonid; Wheeler, Steven E.; Ticknor, Brian W.; Ahmed, Musahid; Leone, Stephen R.; Allen, Wesley D.; Schaefer, Henry F.; Duncan, M. A.

doi:10.1021/ja072526q

Cited by 90 publications

(114 citation statements)

References 144 publications

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“…The C 3 has 12 valence electrons which group into 5 (degenerated) states with a large gap of about 7 eV between the two deepest levels and the three higher ones. Our calculated value of the IP for C 3 , E IP = −ε 5 = 10.8 eV, is in fair agreement with other calculations (12.0 eV [44,45]) and experimental measurements (11.6 eV [46], 12.1 eV [47], and 13.0 eV [48]). Our calculated IP is a bit too low.…”

Section: Static Properties and Optical Responsesupporting

confidence: 91%

Multiplasmon excitations in electron spectra of small systems irradiated by swift charged projectiles

et al. 2015

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Abstract. We investigate the kinetic-energy spectrum of electrons emitted from an excited many-electron system, often called photo-electron spectrum (PES). We are particularly interested on the impact of resonant modes of the system on PES. To this end, we consider three systems with strong resonances, a Mg atom, the small alkaline cluster K9 + , and the small carbon chain C3. To avoid dominant frequencies in the excitation process, we consider a collision with a fast ion which is realized by an instantaneous boost of the valence electrons, a process which excites all frequencies with equal weight. The electron dynamics is investigated from a theoretical perspective using time-dependent density-functional theory augmented by an average-density self-interaction correction. We observe patterns which are similar to PES usually obtained after irradiation by a laser pulse, in particular the appearance of clear peaks. We show that these patterns are driven by strong resonance modes of the system. Resonances are thus found to be another source of peaks in the PES, besides photons (when present) with definite frequencies.

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Section: Static Properties and Optical Responsesupporting

confidence: 91%

Multiplasmon excitations in electron spectra of small systems irradiated by swift charged projectiles

et al. 2015

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“…Clusters have naturally been the subject of numerous experimental and theoretical studies in recent years. [2][3][4][5][6][7][8] There are many potential technological applications of nanoclusters. Several metallic clusters have been shown to be very active catalysts 9,10 due to their high surface-area-to-volume ratios and unusual surface structures.…”

Section: Introductionmentioning

confidence: 99%

Quantum Monte Carlo studies of covalent and metallic clusters: Accuracy of density functional approximations

et al. 2009

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To assess the accuracy of exchange-correlation approximations within density functional theory ͑DFT͒, diffusion quantum Monte Carlo ͑DMC͒ and DFT methods are used to calculate the energies of isomers of three covalently bonded carbon and boron clusters ͑C 20 , B 18 , and B 20 ͒, and three metallic aluminum and copper clusters ͑Al 13 , Al 55 , and Cu 13 ͒. We find that local and semilocal DFT methods predict the same energy ordering as DMC for the metallic clusters but not for the covalent clusters, implying that the DFT functionals are inadequate in such systems. In addition, we find that DFT fails to describe energy reductions arising from Jahn-Teller distortions.

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“…The ionization potentials of Pt, b Pt = 8.95868(11) eV [37], Os, b Os = 8.43823 (20) eV [38], and 12 C 16 , b C16 = 8(1) eV [39], were used for the calculation of Q values and mass excesses. In the case of b C16 the uncertainty was inflated to 1 eV due to significant deviations of [39] and [40] on the determination of the first ionization potential of carbon clusters up to C 15 . For 12 C 16 also the molecular binding energy of 97.3(27) eV must be considered.…”

Section: Resultsmentioning

confidence: 99%

Double resonant enhancement in the neutrinoless double-electron capture ofPt190

et al. 2016

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Background: The observation of neutrinoless double-beta transitions would indicate physics beyond the standard model as the lepton number conservation is violated. For a complete degeneracy in the energy of the initial and final states, the neutrinoless double-electron capture is resonantly enhanced. This shortens the half-life to similar orders of magnitude as the neutrinoless double-beta decay and expands the set of nuclei for the search of neutrinoless double-beta transitions as the observation of either process would be equally likely. Purpose: In order to clearly identify transitions that are resonantly enhanced, among other parameters the total energy of the decay, Qεε, needs to be measured very precisely. Of the twelve initially identified candidates, the last remaining decay without a precise Qεε was 190 Pt(0νεε) 190 Os. Method: The Qεε value was determined with the Penning trap mass spectrometer LEBIT by measuring the ratio of the cyclotron frequencies of 190 Pt + and 190 Os + in a 9.4 T superconducting magnet. Result: The Qεε value was determined to be 1401.57(47) keV with an uncertainty reduction of an order of magnitude compared to its previously known value. The absolute value is shifted by 17.17(623) keV relative to the previously accepted one. Furthermore, the mass value of 190 Pt was found to be shifted by more than three standard deviations. In addition we improved the mass values for 186,190 Os, 194 Pt. Conclusion: Transitions to the two nuclear excited states of 190 Os with 1326.9(5) keV and 1387.00(2) keV energy were identified to be resonantly enhanced within a 1σ uncertainty. The significantly reduced uncertainty of Qεε confirmed the potential for a resonantly enhanced transition.

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Ionization Thresholds of Small Carbon Clusters: Tunable VUV Experiments and Theory

Cited by 90 publications

References 144 publications

Multiplasmon excitations in electron spectra of small systems irradiated by swift charged projectiles

Multiplasmon excitations in electron spectra of small systems irradiated by swift charged projectiles

Quantum Monte Carlo studies of covalent and metallic clusters: Accuracy of density functional approximations

Double resonant enhancement in the neutrinoless double-electron capture ofPt190

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