Production of carbon clusters C3 to C12 with a cryogenic buffer-gas beam source

Straatsma, Cameron; Fabrikant, Maya; Douberly, Gary E.; Lewandowski, H. J.

doi:10.1063/1.4995237

Cited by 7 publications

(5 citation statements)

References 54 publications

(68 reference statements)

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“…31,32 Infrared spectra have been obtained for linear C n clusters up to n=13 in the gas phase 3,33 and in a Ne matrix. 34 Ionization potentials for neutral C n (n=2-15) clusters have been measured using tunable VUV radiation. 35 Negatively charged carbon clusters have been investigated using photoelectron spectroscopy, 36,37 matrix isolation spectroscopy, 29,38 and resonance enhanced photodetachment spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Electronic spectra of positively charged carbon clusters—C2n+ (n = 6–14)

Buntine

Cotter

Jacovella

et al. 2021

The Journal of Chemical Physics

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Electronic spectra are measured for mass-selected C2n+(n = 6–14) clusters over the visible and near-infrared spectral range through resonance enhanced photodissociation of clusters tagged with N2 molecules in a cryogenic ion trap. The carbon cluster cations are generated through laser ablation of a graphite disk and can be selected according to their collision cross section with He buffer gas and their mass prior to being trapped and spectroscopically probed. The data suggest that the C2n+(n = 6–14) clusters have monocyclic structures with bicyclic structures becoming more prevalent for C22+ and larger clusters. The C2n+ electronic spectra are dominated by an origin transition that shifts linearly to a longer wavelength with the number of carbon atoms and associated progressions involving excitation of ring deformation vibrational modes. Bands for C12+, C16+, C20+, C24+, and C28+ are relatively broad, possibly due to rapid non-radiative decay from the excited state, whereas bands for C14+, C18+, C22+, and C26+ are narrower, consistent with slower non-radiative deactivation.

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Section: Introductionmentioning

confidence: 99%

Electronic spectra of positively charged carbon clusters—C2n+ (n = 6–14)

Buntine

Cotter

Jacovella

et al. 2021

The Journal of Chemical Physics

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“…These fullerene bands accompany the so-called aromatic infrared bands (AIBs), which trace polycyclic aromatic aliphatic mixed hydrocarbons widely observed in the ISM [24][25][26][27][28][29][30]. Interestingly, infrared spectroscopy was also used to characterize smaller carbon clusters in laboratory experiments by Straatsma and coworkers [10].…”

Section: Introductionmentioning

confidence: 99%

“…From a few atoms to bulk matter, carbon clusters show a significant ability to hybridize in sp, sp 2 or sp 3 chemical bonds, reflecting at finite size the wide allotropy of bulk carbon matter. Depending on experimental conditions, carbon clusters can be produced into a very large variety of isomers that have been probed by many groups for more than two decades [1][2][3][4][5][6][7][8][9][10][11]. Below about 20 carbon atoms, (1D) chains and (2D) rings have been identified as the most stable isomers [1,4,12] while (3D) fullerenes were shown to be the most stable form of larger carbon clusters [7,13].…”

Section: Introductionmentioning

confidence: 99%

Simulating the structural diversity of carbon clusters across the planar-to-fullerene transition

et al. 2019

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Together with the second generation REBO reactive potential, replica-exchange molecular dynamics simulations coupled with systematic quenching were used to generate a broad set of isomers for neutral C n clusters with n = 24, 42, and 60. All the minima were sorted in energy and analyzed using order parameters to monitor the evolution of their structural and chemical properties. The structural diversity measured by the fluctuations in these various indicators is found to increase significantly with energy, the number of carbon rings, especially 6-membered, exhibiting a monotonic decrease in favor of low-coordinated chains and branched structures. A systematic statistical analysis between the various parameters indicates that energetic stability is mainly driven by the amount of sp 2 hybridization, more than any geometrical parameter. The astrophysical relevance of these results is discussed in the light of the recent detection of C 60 and C + 60 fullerenes in the interstellar medium.

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“…A radically different approach for creating intense beams of molecules and molecular radicals is the so-called cryogenic buffer gas beam source, first introduced by Maxwell et al [11] and further developed by Patterson and Doyle [12], van Buuren et al [13], Barry et al [14], Hutzler et al [15,16] and others. In this method, molecules are introduced into a cold cell by a capillary [11-13, 17, 18], by laser ablation of a target containing a precursor [11,12,14,15,[19][20][21][22][23][24][25][26][27][28][29][30] or by letting laser ablated atoms react with a donor gas [31][32][33][34]. The hot molecules are cooled by collisions with cold helium or neon buffer gas.…”

Section: Introductionmentioning

confidence: 99%

Influence of source parameters on the longitudinal phase-space distribution of a pulsed cryogenic beam of barium fluoride molecules

Mooij,

Bethlem,

Boeschoten

et al. 2024

New J. Phys.

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Recently, we have demonstrated a method to record the longitudinal phase-space distribution of a pulsed cryogenic buffer gas cooled beam of barium fluoride molecules. In this paper, we use this method to determine the influence of various source parameters. Besides the expected dependence on temperature and pressure, the forward velocity of the molecules is strongly correlated with the time they exit the cell, revealing the dynamics of the gas inside the cell. Three observations are particularly noteworthy: (1) The velocity of the barium fluoride molecules increases rapidly as a function of time, reaches a maximum 50-200\;$\upmu$s after the ablation pulse and then decreases exponentially. We attribute this to the buffer gas being heated up by the plume of hot atoms released from the target by the ablation pulse and subsequently being cooled down via conduction to the cell walls. (2) The time constant associated with the exponentially decreasing temperature increases when the source is used for a longer period of time, which we attribute to the formation of a layer of isolating dust on the walls of the cell. By thoroughly cleaning the cell, the time constant is reset to its initial value. (3) The velocity of the molecules at the trailing end of the molecular pulse depends on the length of the cell. For short cells, the velocity is significantly higher than expected from the sudden freeze model. We attribute this to the target remaining warm over the duration of the molecular pulse giving rise to a temperature gradient within the cell. Our observations will help to optimize the source parameters for producing the most intense molecular beam at the target velocity.

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Production of carbon clusters C3 to C12 with a cryogenic buffer-gas beam source

Cited by 7 publications

References 54 publications

Electronic spectra of positively charged carbon clusters—C2n+ (n = 6–14)

Electronic spectra of positively charged carbon clusters—C2n+ (n = 6–14)

Simulating the structural diversity of carbon clusters across the planar-to-fullerene transition

Influence of source parameters on the longitudinal phase-space distribution of a pulsed cryogenic beam of barium fluoride molecules

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