Cross sections for photoionization of fullerene molecular ions Cn+ with n = 40, 50, 70, 76, 78, and 84

Abstract

Absolute cross-section measurements are reported for single photoionization of C + n fullerene molecular ions (n = 40, 50, 70, 76, 78 and 84) in the photon energy range 18 -70 eV. The experiments were performed by merging a mass and charge selected beam of C + n molecular ions with a beam of monochromatized synchrotron radiation and measuring the yield of C 2+ n product ions as a function of the photon energy. Oscillator strengths determined by integrating the measured cross sections over this energy range exhibit a linear dependence on n. The cross sections are parametrized by fits to three Lorentzian functions to represent plasmon excitations and a linear function for direct ionization. The highest energy resonance in the data near 46 eV is similar to that previously observed in single photoionization of C60 and may be attributable to a harmonic of the dominant surface plasmon resonance near 23 eV.

Experimental studies on photoabsorption by endohedral fullerene ions with a focus on Xe@C60 + confinement resonances

“…An advantage is the potential for the measurement of absolute cross sections for different final reaction channels that involve ionization or fragmentation of the initial ion. Studies of photoprocesses of fullerene ions by employing the merged-beams technique comprise single ionization of + C q 60 with = q 1, 2, 3 [16], single ionization of Sc 3 N@C 80 + and Ce@C 82 + [17], single ionization of + C 60 and + C 80 [18], single and double ionization of Ce@C 82 + and + C 82 [19], double ionization of Ce@C 82 + [20], double ionization of Xe@C 60 + accompanied by ejection of a C 2 dimer [21], double and triple detachment of -C 60 ions [22], double ionization of Xe@C 60 + and + C 60 with ejection of N C 2 dimers ( = N 0, 1, 2, 3) [23], single and multiple ionization with fragmentation of Lu 3 N@C 80 q+ ( = q 1, 2, 3) [24], single ionization of + C 60 with ejection of N C 2 ( = N 0, 1, 2, 3, 4, 5, 6, 7) dimers [25], single ionization of + C n ( = n 40, 50, 70, 76, 78, 84) [26], ionization and fragmentation of Sc 3 N@C 80 + and Sc 3 N@C -80 ions [27].…”

Hydrodynamic model of the collective electron resonances in C60 fullerene

“…The studies described in the references above have allowed to reveal a number of important features and characteristics of the fullerene polarization processes. There was predicted [1] and confirmed experimentally [2][3][4][5] the existence of the so-called giant resonance of C 60 molecule in the frequency range ~ 20 -40 eV, associated with the excitation of the dipole surface plasmons. The plasmon resonances spectra of this molecule were studied in different aspects: based on the quantum [5][6][7][8][9][10][11] and semiclassical [12][13][14][15][16][17][18] approaches (including the nonlinear effects in the processes of the one-photon and multi-photon absorption [9]), with the dipole and high multipoles excitations taken into account [6][7][8][14][15][16][17][18], under different manifestation conditions (excitation by the optical radiation [5,[9][10][11][12][13][14][15][16][17][18] and moving electrons [6][7][8]), and different approximations of electron density distribution (homogeneous…”

“…Studies on the dynamical polarizability of the spherical plasma shells interacting with the fields of different external sources are of interest in connection with the problems of the observed scattering and absorption spectra identification of the fullerenes (and, in particular, C 60 molecule), displaying oscillatory features of plasma-like systems due to a great number of the valence (delocalized) electrons [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Related circle of problems arises also when studying metamaterials made on the basis of shell-like structures (for example, semiconductor quantum dots or metal-dielectric nanoparticles) [19][20][21][22][23][24][25][26][27].…”

Molecular-size effects on diffraction resonances in positronium formation from fullerenes

“…The work further motivates a new research direction to apply Ps formation spectroscopy to gas-phase nanosystems which began with our earlier published research [45,46], since fullerenes currently enjoy significant attraction in precision measurements. Fullerenes [65] and metallic nanoparticles [43,66] are nowadays available in gas-phase. However, probing the target-state differential Ps-signals is still challenging for current techniques [67].…”