Large carbon cluster ion formation by laser ablation of polyimide and graphite

LASER IONIZATION MASS SPECTROMETRY AT 55: QUO VADIS?

Laser ionization mass spectrometry (LIMS) was one of the first practical methods developed for in situ analysis of the surfaces of solid samples. This review will encompass several aspects related to this analytical method. First, we will discuss the process of laser ionization, the influence of the laser type on its performance, and imaging capabilities of this method. In the second chapter, we will follow the historic development of LIMS instrumentation. After a brief overview of the first-generation instruments developed in 1960-1990 years, we will discuss in detail more recent designs, which appeared during the last 2-3 decades. In the last part of our review, we will cover the recent applications of LIMS for surface analysis. These applications include various types of analyses of solid inorganic, organic, and heterogeneous samples, often in combination with depth profiling and imaging capability.

Probing Laser Plasma Dynamics Using High-Order Harmonics Generation in Carbon-Containing Nanomaterials

We study high-order harmonics generation from plasmas generated from graphite, fullerenes, carbon nanotubes, carbon nanofibers, diamond nanoparticles, and graphene. Our approach utilizes a heating nanosecond laser pulse to produce plasmas that serve as the media for high harmonic generation from a subsequent driven femtosecond laser pulse. High harmonics are generated at different time delays following the plasma formation, which allows us to analyze the spreading of species with different masses. We analyze the harmonic yields from species of single carbon atom, 60 atoms (fullerene), 106 atoms (diamond nanoparticles), 109 atoms (CNTs and CNFs), and even much larger species of graphene sheets. The harmonic yields are analyzed in the range of 100 ns–1 ms delays. The harmonic yields were significantly higher within the 200 ns–0.5 µs range, but no harmonic is observed between 10 µs–1 ms. Our observations show that, at the optimal ablation of atoms and clusters, the laser-induced plasmas produced on the surfaces of different carbon-contained species spread out from targets with the comparable velocities.

New insights on laser-induced graphene electrodes for flexible supercapacitors: tunable morphology and physical properties

In certain polymers the graphenization of carbon atoms can be obtained by laser writing owing to the easy absorption of long-wavelength radiation, which generates photo-thermal effects. On a polyimide surface this process allows the formation of a nanostructured and porous carbon network known as laser-induced graphene (LIG). Herein we report on the effect of the process parameters on the morphology and physical properties of LIG nanostructures. We show that the scan speed and the frequency of the incident radiation affect the gas evolution, inducing different structure rearrangements, an interesting nitrogen self-doping phenomenon and consequently different conduction properties. The materials were characterized by infrared and Raman spectroscopy, XPS elemental analysis, electron microscopy and electrical/electrochemical measurements. In particular the samples were tested as interdigitated electrodes into electrochemical supercapacitors and the optimized LIG arrangement was tested in parallel and series supercapacitor configurations to allow power exploitation.

Berkelium and californium organometallic ions

Organoberkelium and organocalifornium ions were produced for the first time by laser ablation of 249Bk2O_{3} and 249Cf2O_{3} dispersions in polyimide, followed by analysis with time-of flight mass spectrometry. The primary products formed were: BkCH3 +, BkC2 +, AnC2H+, AnCN+, AnC4H+, An(OH)(CN)+, AnOCN+, AnOH+, An(OH)2 + and AnO+ (where An=Bk or Cf). Several of these complexes represent the first organoactindes in which Bk and Cf are directly bonded to carbon. The compositions and abundance distributions of the products are effectively evaluated in the context of a bonding model which requires one or two non-5f valence electrons at the An+ center for participation in direct An+-C bonding to form the monovalent or divalent complexes. Both Bk and Cf exhibit a propensity to form "monovalent" organoactinides in which the metal center forms a single σ-type bond to the organic moiety. Most earlier actinides form "divalent" complexes having two An+-C bonds. A few small oxide cluster ions, An m O n + (m=2 or 3) were identified, demonstrating the feasibility of preparing clusters for the heavy actinides. The energetics underlying the present results are discussed with an emphasis on the evidently pivotal position of Bk in the actinide series.

Rarefaction shock wave: formation under short pulse laser ablation of solids

We investigate formation, dynamics, and decay of the rarefaction shock wave under the conditions of ultrashort pulse laser ablation of solids. On the basis of the Euler equation and the van der Waals equation, we consider the planar and spherical expansion into vacuum matter heated instantaneously above the thermodynamic critical temperature. When the expansion occurs along an abnormal adiabat, in a part of which ( partial differential(2)p/ partial differentialv(2))/(S)<0, a rarefaction shock wave moving toward the target is formed. After its reflection from the nonvaporized material of the target, a thin dense layer of the expanding material is found to be formed. We suggest that this is the explanation for interference patterns observed experimentally above laser ablated surfaces. It has been speculated that the rarefaction shock wave may be formed on nova outbursts.

Fullerenes in the 1.85-billion-year-old Sudbury impact structure

Fullerenes (C60 and C70) have been identified by laser desorption, laser desorption post-ionization, and high-resolution electron-impact mass spectrometry in shock-produced breccias (Onaping Formation) of the Sudbury impact structure in Ontario, Canada. The C60 isotope is present at a level of a few parts per million. The fullerenes were likely synthesized within the impact plume from the carbon contained in the bolide. The oxidation of the fullerenes during the 1.85 billion years of exposure was apparently prevented by the presence of sulfur in the form of sulfide-silicate complexes associated with the fullerenes.

Poly(amic acid) and polyimide characterization using gas chromatography/mass spectrometry and particle beam liquid chromatography/mass spectrometry

A number of polymers were hydrolyzed in NH4OH and studied using gas chromatography/ mass spectrometry (GC/MS) and particle beam liquid chromatography/mass spectrometry (particle beam LC/MS) techniques. The polymers studied in this report were as follows: BPDA-PDA, BPDA-PDA-ODA, BPDA-PDA-GFDA, PMDA-ODA, and BTDA-APB. Some of the polymer samples were hydrolyzed in both their acid and imide forms to see if any mass spectrometric differences could be detected. ln all cases, the acid and imide spectra looked the same. GC/MS was unable to determine either the amine or acid portion of these polymers via a direct injection of the sample, but when the samples were first extracted with diethyl ether and this ether extract was injected into the chromatograph, the amine portion of the polymers was readily detected. The acid portion was, again, not detected in either the sample or the ether extract. The particle beam was able to detect both the amine and acid monomeric units in the nonextracted sample.

Production of Metallo-Carbohedrenes in the Solid State

Macroscopic quantities of the metallo-carbohedrenes TI(8)C(12) and V(8)C(12) have been synthesized with an arc discharge technique. Mass spectroscopy of raw soot samples generated in both an alternating and direct current arc between two metal-graphite powder composite electrodes establishes that the titanium and vanadium analogs of the metallo-carbohedrenes have been produced. An estimated yield of approximately 1 percent is obtained, and significantly, the products are stable in air.

Mass spectrometry and fullerenes

This article presents, from amass spectrometry perspective, an historical account of research on gas-phase carbon clusters, which has led to the discovery of another form of carbon, fullerenes. In addition, more recent mass spectrometric studies on analysis of fullerene derivatives and synthesis of doped fullerenes are described. The early, strong evidence for certain "magic number" carbon clusters, most notably C60 (buckminsterfullerene), was obtained largely from mass spectrometric experiments. These studies led to the controversial postulation of the soccerball structure for C60, which provoked increased experimental and theoretical efforts. This research eventually resulted in the discovery of a simple method by which large quantities of fullerenes can be produced. The availability of these new, all-carbon molecules has motivated a broad range of synthetic and characterization studies that are expanding at a frenetic pace. Mass spectrometry not only played a critical role in the discovery of fullerenes but also now is crucial for determination of the unusual chemical and physical properties of fullerenes and fullerene-based materials.