Cluster Ion Beam Research Articles

Research on microscopic structure–activity relationship of AP particle–matrix interface in HTPB propellant

Abstract The matrix and particle interface of hydroxyl-terminated polybutadiene (HTPB) propellant is the weakest part of its mechanical properties, making it prone to dewetting damage and destroying the structural integrity of the propellant. This article uses nano-indentation, gas cluster ion beam etching, and X-ray photoelectron spectroscopy experimental analyses to study the physicochemical properties of the interface and subsequently construct a microscopic model for the HTPB matrix and ammonium perchlorate particle interface. The model fully considers the existing forms of curing agent toluene diisocyanate, bonding agent Tris (2-methyl-aziridine) phosphine oxide (MAPO), and the aging products of the propellant in the interface structure. Meanwhile, the physicochemical properties, mechanical properties, and adhesive properties of the interface under different tensile loading conditions were analyzed. The results indicate that the bonding agent MAPO significantly enhances the mechanical and adhesive properties of the interface. The interface is sensitive to changes in temperature and tensile rate, and the aged interface is more fragile.

Reactive Gas Cluster Ion Beams for Enhanced Drug Analysis by Secondary Ion Mass Spectrometry.

In this study, we investigate the formation and composition of Gas Cluster Ion Beams (GCIBs) and their application in Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) analysis. We focus on altering the carrier gas composition, leading to the formation of (Ar/CO2)n or (H2O)n GCIBs. Our results demonstrate that the addition of a reactive species (CO2) to water GCIBs significantly enhances the secondary ion yield of small pharmaceutical compounds in the positive ion mode. In negative ion mode, the addition of CO2 resulted in either a positive enhancement or no effect, depending on the sample. However, an excess of CO2 in the carrier gas leads to the formation of carbon dioxide clusters, resulting in reduced yields compared to that of water cluster beams. Cluster size also plays a crucial role in overall yields. In a simple two-drug system, CO2-doped water clusters prove effective in mitigating matrix effects in positive ion mode compared to pure water cluster, while in negative ion mode, this effect is limited. These clusters are also applied to the analysis of drugs in a biological matrix, leading to more quantitative measurements as shown by a better fitting calibration curve. Overall, the doping of water clusters with small amounts of a reactive gas demonstrates promising benefits for higher sensitivity, higher resolution molecular analysis, and imaging using ToF-SIMS. The effectiveness of these reactive cluster beams varies depending on the experimental parameters and sample type.

Towards a better understanding of the surface smoothing effect in gas cluster ion beam processing with molecular dynamics simulation and experiment

In recent years, the application of gas cluster ion beam (GCIB) technology has made great progress. Due to the similar essence of a monoatomic ion beam, the GCIB also shows flashes of brilliance in material processing. It has been reported that smoothness can be greatly improved after the rough surface is bombarded by the GCIB. This indicates that the GCIB processing has great potential in optical fabrication. Although the surface smoothing effect has been investigated, there is still a lack of dynamic micro-analysis for GCIB processing, which is limited for better understanding the mechanism of smoothing effect. In this paper, the surface smoothing effect in GCIB processing is explicitly investigated with molecular dynamics (MD) simulation and experiment. The principle of GCIB processing is compared with the traditional monoatomic ion-beam based processing, and details of the MD simulation procedure are introduced. Based on this, the dynamic micro-analysis of GCIB processing is conducted under different processing conditions. The simulations reveal the phenomena of atomic removal and migration in GCIB processing, which plays an important role in explaining the mechanism of surface smoothing effect. The experiment was performed on the silicon substrate with the in-house GCIB processing machine. The results indicate that the initial rough surface with dense protrusions can be greatly smoothed, and the root mean square (RMS) value is reduced from 0.586 nm to 0.191 nm. Both simulation and experiment can provide a better understanding of smoothing effect mechanism in GCIB processing.

Characterization of silicon-based chromium (VI) replacement coatings by using time-of-flight secondary ion mass spectrometry and salt spray tests

This paper proposes an innovative approach in characterization of silicon-based chromium (VI) replacement coatings on an Al substrate by using, salt spray tests and time-of-flight secondary ion mass spectrometry (ToF-SIMS) performed in profile mode by a gas cluster ion beam source (GCIB). While salt spray tests highlight the difference in anticorrosion behaviour, ToF-SIMS provides molecular information on the entire coating and even down to the interface with the Al substrate. ToF-SIMS revealed Si2O2+ and SiOAl + fragments which both contribute to understanding the differences in the anticorrosion performance which are found in the salt spray tests. Si2O2+ moieties relate to the cross-linking density of the coating and subsequently determines the barrier properties. SiOAl+ originates from the interface and characterizes the actual “conversion” of Al at the interface by the deposited layer. The differences in the profile of Si2O2+ and SiOAl + explained the respective anticorrosion performance. From the tested coatings PCT161 showed the highest intensity for both Si2O2+ and SiOAl + while simultaneously performing the best results in the salt spray test. These observations highlight that Si2O2+ and SiOAl + fragments are good indicators of anticorrosion performance and are confirmed by salt spray tests. Moreover, PCT161 and PCT146 are true conversion coatings capable of replacing chromium-based systems.

Nanoscale pattern formation on surfaces by cluster ion beam irradiation

Ion beam sputtering is a solid-surface nanostructuring procedure applicable to any type of material. In this study, we are interested in the bombardment of a metallic surface, specifically, of a Co(110) surface bombarded with Ar clusters at oblique incidence. The bombardment with clusters accentuates the effect of surface ripple formation. Sputter erosion and surface atomic redistribution are the processes that determine the morphological evolution of the surface from the collisional point of view. The importance of these processes was analyzed for different angles of incidence in the bombardment with very small clusters and atoms while always maintaining the same fluence. The sputter yield increases with the number of atoms in the cluster for angles greater than 50°; while for the rest, it barely experiences any increase. Unlike sputtering, displacements increase as the cluster size increases above the critical angle. Moreover, horizontal displacement only shows some sign of saturation for angles close to the normal. An analysis of redistributed volumes and previous data suggest that sputtering drives the ripple effect for grazing angles and ones close to these. It is also responsible for the enhancement effect in the cluster bombardment. For the rest of the angles, the weight of the redistribution is decisive. There is a proportional relationship between the emptied volume and the horizontal displacement.

Molecular Dynamics Simulations of Soft and Reactive Landing of Proteins Desorbed by Argon Cluster Bombardment.

Reactive molecular dynamics (MD) simulations were conducted to investigate the soft and reactive landing of hyperthermal velocity proteins transferred to a vacuum using large argon clusters. Experimentally, the interaction of argon cluster ion beams (Ar1000-5000+) with a target biofilm was previously used in such a manner to transfer lysozymes onto a collector with the retention of their bioactivity, paving the way to a new solvent-free method for complex biosurface nanofabrication. However, the experiments did not give access to a microscopic view of the interactions needed for their full understanding, which can be provided by the MD model. Our reactive force field simulations clarify the landing mechanisms of the lysozymes and their fragments on collectors with different natures (gold- and hydrogen-terminated graphite). The results highlight the conditions of soft and reactive landing on rigid surfaces, the effects of the protein structure, energy, and incidence angle before landing, and the adhesion forces with the collector substrate. Many of the obtained results can be generalized to other soft and reactive landing approaches used for biomolecules such as electrospray ionization and matrix-assisted laser desorption ionization.

Gas Cluster Ion Beam-Assisted Deposition for Fabricating Dry Multilayers Containing Enzyme and Substrate with On-Demand Release.

Gas cluster ion beam (GCIB)-assisted deposition is used to build multilayered protein-based structures. In this process, Ar3000-5000+ clusters bombard and sputter molecules from a reservoir (target) to a collector, an operation that can be sequentially repeated with multiple targets. The process occurs under a vacuum, making it adequate for further sample conservation in the dry state, since many proteins do not have long-term storage stability in the aqueous state. First of all, the stability in time and versatility in terms of molecule selection are demonstrated with the fabrication of peptide multilayers featuring a clear separation. Then, lysozyme and trypsin are used as protein models to show that the activity remaining on the collector after deposition is linearly proportional to the argon ion dose. The energy per atom (E/n) of the Ar clusters is a parameter that was also changed for lysozyme deposition, and its increase negatively affects activity. The intact detection of larger protein molecules by SDS-PAGE gel electrophoresis and a bioassay (trypsin at ≈25 kDa and glucose oxidase (GOx) at ≈80 kDa) is demonstrated. Finally, GOx and horseradish peroxidase, two proteins involved in the same enzymatic cascade, are successively deposited on β-d-glucose to build an on-demand release material in which the enzymes and the substrate (β-d-glucose) are combined in a dry trilayer, and the reaction occurs only upon reintroduction in aqueous medium.

Highly sensitive electron-beam-induced X-ray detection from liquid using SiNx membrane ultra-thinned by gas cluster ion beams

We aimed to improve the detection sensitivity for liquid measurement by developing an ultrathin photoelectron transmission window (SiNx membrane) for liquid cells via X-ray photoelectron spectroscopy or X-ray photoelectron emission microscopy at an ultrahigh vacuum. The membrane using gas-cluster ion beams (GCIB) was thinned, and its burst pressure was compared with those of membranes thinned with atomic 400 eV Ar+ ions. The SiNx membranes thinned by GCIB had approximately 2.5 times higher burst pressure than Ar+ ions. In addition, the improved sensitivity of the characteristic X-ray from liquid water induced by low-energy electrons was investigated. With the use of the 4.5 nm-thick SiNx membrane etched by GCIB, the X-ray intensity became 1.6 times higher than those of the 11 nm-thick pristine membrane at the electron beam (EB) energy of 1.5 keV. This result showed a good agreement with Monte Carlo simulation results of the EB-induced X-ray emission from liquid water beneath the SiNx membrane.

Efficient nanopatterning of Ge surface induced by oblique argon cluster ion beam

The evolution of the self-assembled nanostructures formed on the Ge (100) surface as a result of sputtering by an obliquely incident argon cluster ion beam is studied. The bombardment was carried out with Ar1000+ ions at energy of 10 keV and angle of incidence of 60˚ from the normal while varying the ion fluence from 8 × 1014 up to 2 × 1016 ions/cm2. It is found that parallel-mode ordered ripples with significant aspect ratios can be produced on the Ge surface at a minimum sputtering depth. Such nanostructures have not previously been formed on the Ge surface with conventional argon ions. Our findings prove that argon cluster ion beam is effective for nanopatterning the surface of single-component semiconductors.

From surface to core: Comprehensive ToF-SIMS insights into pharmaceutical tablet analysis

This study presents an innovative approach to pharmaceutical analysis using time-of-flight secondary ion mass spectrometry (ToF-SIMS) to investigate tablets containing paracetamol in the solid state without the need for traditional pretreatment methods (dissolution, filtration, etc.). Employing both MS1 and MS2 ToF-SIMS spectra, signals characteristic of paracetamol and a fragmentation mechanism were assigned. Some findings challenge previous interpretations of certain ToF-SIMS signals attributed to paracetamol, highlighting the need for reevaluation. Moreover, as the sample was used without any pretreatment (a purchased tablet), which has a complex matrix, the resulting ToF-SIMS mass spectra can suffer from spectral interferences. The use of multivariate statistical analysis resulted in the assignment of unique signals for paracetamol. Additionally, ToF-SIMS imaging was utilized with high mass and lateral resolution, employing the delayed-extraction ToF analyzer mode, to image the two-dimensional distribution of species on the tablet’s surface with an emphasis on paracetamol distribution. The use of a gas cluster ion beam (GCIB) sputtering source in association with ToF-SIMS enabled the visualization of the three–dimensional distribution of species within the tablet. This thorough investigation advances knowledge regarding the characterization of paracetamol and offers the examination of pharmaceuticals without sample pretreatment with elemental and molecular-specific information.

Utilizing Constant Energy Difference between sp-Peak and C 1s Core Level in Photoelectron Spectra for Unambiguous Identification and Quantification of Diamond Phase in Nanodiamonds.

The modification of nanodiamond (ND) surfaces has significant applications in sensing devices, drug delivery, bioimaging, and tissue engineering. Precise control of the diamond phase composition and bond configurations during ND processing and surface finalization is crucial. In this study, we conducted a comparative analysis of the graphitization process in various types of hydrogenated NDs, considering differences in ND size and quality. We prepared three types of hydrogenated NDs: high-pressure high-temperature NDs (HPHT ND-H; 0-30 nm), conventional detonation nanodiamonds (DND-H; ~5 nm), and size- and nitrogen-reduced hydrogenated nanodiamonds (snr-DND-H; 2-3 nm). The samples underwent annealing in an ultra-high vacuum and sputtering by Ar cluster ion beam (ArCIB). Samples were investigated by in situ X-ray photoelectron spectroscopy (XPS), in situ ultraviolet photoelectron spectroscopy (UPS), and Raman spectroscopy (RS). Our investigation revealed that the graphitization temperature of NDs ranges from 600 °C to 700 °C and depends on the size and crystallinity of the NDs. Smaller DND particles with a high density of defects exhibit a lower graphitization temperature. We revealed a constant energy difference of 271.3 eV between the sp-peak in the valence band spectra (at around 13.7 eV) and the sp3 component in the C 1s core level spectra (at 285.0 eV). The identification of this energy difference helps in calibrating charge shifts and serves the unambiguous identification of the sp3 bond contribution in the C 1s spectra obtained from ND samples. Results were validated through reference measurements on hydrogenated single crystal C(111)-H and highly-ordered pyrolytic graphite (HOPG).

Pressure resistance evaluation of an ultrathin SiNx membrane etched by a gas cluster ion beam

In this study, reactive etching of a SiNx free-standing membrane with a thickness of a few nanometers was performed using a gas cluster ion beam (GCIB) and the pressure resistance of the membrane with respect to its thickness was evaluated. The low-damage irradiation effect of a 7 keV GCIB in an acetylacetone (Hacac) atmosphere enabled the etching to retain its pressure resistance compared with that of 400 eV Ar+ beam irradiation. In a previous study, it was shown that irradiation of SiNx films with Ar plasma of several hundred eV causes defects in the bonding network of the Si–N bond and the network is easily oxidized. XPS measurements on SiNx films after GCIB etching with Hacac and Ar+ beam irradiation showed that the composition of the Si–O bond was smaller with GCIB irradiation compared to Ar+ beam irradiation. This indicates that GCIB etching with Hacac can suppress the formation of defects in the Si–N network, which reduces the degradation of the pressure resistance.

Multimodal mass spectrometry imaging identifies cell-type-specific metabolic and lipidomic variation in the mammalian liver

Spatial single-cell omics provides a readout of biochemical processes. It is challenging to capture the transient lipidome/metabolome from cells in a native tissue environment. We employed water gas cluster ion beam secondary ion mass spectrometry imaging ([H2O]n>28K-GCIB-SIMS) at ≤3μm resolution using a cryogenic imaging workflow. This allowed multiple biomolecular imaging modes on the near-native-state liver at single-cell resolution. Our workflow utilizes desorption electrospray ionization (DESI) to build a reference map of metabolic heterogeneity and zonation across liver functional units at tissue level. Cryogenic dual-SIMS integrated metabolomics, lipidomics, and proteomics in the same liver lobules at single-cell level, characterizing the cellular landscape and metabolic states in different cell types. Lipids and metabolites classified liver metabolic zones, cell types and subtypes, highlighting the power of spatial multi-omics at high spatial resolution for understanding celluar and biomolecular organizations in the mammalian liver.

Femtosecond laser ablation (fs-LA) XPS – A novel XPS depth profiling technique for thin films, coatings and multi-layered structures

Sputter depth profiling has been employed for XPS/AESdepth profilingsincethe late 1960s. However, for many materials, ion beam induced damage distorts the chemical state information and chemical composition, limiting the value of the analysis. A novelmethodology is presented in which XPS depth profiles are generated using a 160 fs pulse length, 1030 nm peak wavelength femtosecond laser in place of the traditional ion gun. Femtosecond laser ablation (fs-LA) XPS depth profiles are compared with argon monatomic and cluster ion beam depth profilesfor different classes of materials, including ceramics, semiconductors, polymers and metals. In all cases, the XPS spectra recorded following femtosecond laser ablation are fully representative of the original chemical composition and chemical state, with no ablation induced damage. The technique is also shown to be very versatile with ablation rates of <20 nm per pulse being achieved for thin films but profiles to depths of >30 μm are also realisable in practical time scales.fs-LA XPS depth profiling promises to be a very exciting new methodology for the XPS community, complementing sputter depth profiling but avoiding the chemical damage induced by ion beams and offering valuable new depth profiling capabilities.

Sulfide-Based Solid-State Lithium-Sulfur Batteries: An in-Depth Study of the Li-Electrolyte Interface

The development of solid-state batteries has gained significant attention in recent years, owing to their potential to enhance the temperature range and energy density of energy storage devices. Sulfide-based electrolytes are some of the most promising candidates for solid-state batteries, thanks to their high ionic conductivity and low processing temperature. For lithium-sulfur (Li-S) batteries, the transition from liquid to solid electrolytes holds even greater promise. Sulfur is a readily available cathode material known for its high specific capacity, which endows Li-S batteries with remarkable specific energy and favourable environmental and economic impact. In liquid electrolytes however, the solubility of sulfur and lithium polysulfide causes a multitude of issues that hamper the performance of the Li-S system: rapid self-discharge, redox shuttle mechanism during charging, and loss of active sulfur and lithium material due to direct chemical reactivity. Solid-state Li-S cells are not prone to these issues, but they have, of course, issues of their own. Amongst them, the stability of the interface between the electrolyte and the lithium is of crucial importance to allow the use of this very high energy density negative electrode.In the present study, we compare two sulfide electrolytes, Li6PS5Cl and Li7P3S11, and assess their respective stability against lithium. We used innovative methods to characterize the interphase between the sulfide and the lithium without damaging it upon dismantling the cell. The nature and the properties of this interphase was characterised via EIS, XPS and ToF-SIMS.The EIS study showed that Li6PS5Cl forms a much more stable interphase with lithium than Li7P3S11, which is in accordance with most recent results in the literature. The XPS study confirmed the chemical composition of the interphase. Li2S and Li3P were present for both electrolytes. In the case of Li6PS5Cl, LiCl was also identified as expected. Gas cluster ion beam (GCIB) assisted abrasion of the interphase followed by in-situ XPS and ToF-SIMS suggested a separation of the components of the interphase depending on the depth of the abrasion. The interphase was found to be organised as Li2S-, Li3P- or LiCl-rich discrete layers, with the Li2S-rich layer being consistently the closest to lithium. This result confirms and completes the most recent research in the field published by Otto et al. in 2022 (doi: 10.1002/admi.202102387).To establish solid-state batteries as a practical energy storage option, it is essential to fully understand and effectively manage the Li-electrolyte interface. These findings suggest that thanks to the relative stability of its interface with lithium, Li6PS5Cl is the better option for solid-state lithium metal cells. It also sheds light on the reasons why this interface is more stable. The self-assembled lamellar structure of the interphase could also inspire strategies to better control the stability of solid electrolytes versus lithium.

Direct identification of interfacial degradation in blue OLEDs using nanoscale chemical depth profiling

Understanding the degradation mechanism of organic light-emitting diodes (OLED) is essential to improve device performance and stability. OLED failure, if not process-related, arises mostly from chemical instability. However, the challenges of sampling from nanoscale organic layers and interfaces with enough analytical information has hampered identification of degradation products and mechanisms. Here, we present a high-resolution diagnostic method of OLED degradation using an Orbitrap mass spectrometer equipped with a gas cluster ion beam to gently desorb nanometre levels of materials, providing unambiguous molecular information with 7-nm depth resolution. We chemically depth profile and analyse blue phosphorescent and thermally-activated delayed fluorescent (TADF) OLED devices at different degradation levels. For OLED devices with short operational lifetimes, dominant chemical degradation mainly relate to oxygen loss of molecules that occur at the interface between emission and electron transport layers (EML/ETL) where exciton distribution is maximised, confirmed by emission zone measurements. We also show approximately one order of magnitude increase in lifetime of devices with slightly modified host materials, which present minimal EML/ETL interfacial degradation and show the method can provide insight for future material and device architecture development.

Unraveling the Molecular Dynamics of Glucose Oxidase Desorption Induced by Argon Cluster Collision.

The bombardment of a protein multilayer target by an energetic argon cluster ion beam enables protein transfer onto a collector in the vacuum while preserving their bioactivity (iBEAM method). In parallel to this new soft-landing variant, protein transfer in the gas phase is a prerequisite for their characterization by mass spectrometry. The successful transfer of bioactive lysozymes (14 kDa) by cluster-induced soft landing and its mechanistic explanation by molecular dynamics (MD) simulations have sparked an important inquiry: Can heavier biomolecules be desorbed while maintaining their tridimensional structure and hence their bioactivity? To address this question, we employed MD simulations using a reactive force field (ReaxFF). Specifically, the Ar cluster-induced desorption of glucose oxidase from either a gold substrate or a lysozyme underlayer was modeled using the LAMMPS code. First, the force field parameters were trained by computing the dissociation energetics of a series of organic molecules with ReaxFF and DFT, in order to realistically describe N-S and O-S interactions in the bombarded glucose oxidase molecule. Second, bombardment simulations investigated the effects of cluster size (ranging from 1000 to 10000 Ar atoms) and kinetic energy (1.5 and 3.0 eV/atom) on the structural features and energetics of the desorbing glucose oxidase. Our results show that large argon clusters (≥7000) are needed to desorb glucose oxidase from a gold surface, yet protein fragmentation and/or pronounced denaturation occur. However, the transfer of structurally preserved glucose oxidase in the gas phase is predicted by the simulations when an organic layer is used as a substrate.

Improvement of Lipid Detection in Mouse Brain and Human Uterine Tissue Sections Using In Situ Matrix Enhanced Secondary Ion Mass Spectrometry.

The potential of mass spectrometry imaging, and especially ToF-SIMS 2D and 3D imaging, for submicrometer-scale, label-free molecular localization in biological tissues is undisputable. Nevertheless, sensitivity issues remain, especially when one wants to achieve the best lateral and vertical (nanometer-scale) resolution. In this study, the interest of in situ matrix transfer for tissue analysis with cluster ion beams (Bin+, Arn+) is explored in detail, using a series of six low molecular weight acidic (MALDI) matrices. After estimating the sensitivity enhancements for phosphatidylcholine (PC), an abundant lipid type present in almost any kind of cell membrane, the most promising matrices were softly transferred in situ on mouse brain and human uterine tissue samples using a 10 keV Ar3000+ cluster beam. Signal enhancements up to 1 order of magnitude for intact lipid signals were observed in both tissues under Bi5+ and Ar3000+ bombardment. The main findings of this study lie in the in-depth characterization of uterine tissue samples, the demonstration that the transferred matrices also improve signal efficiency in the negative ion polarity and that they perform as well when using Bin+ and Arn+ primary ions for analysis and imaging.

Enhancing Ion Signals and Improving Matrix Selection in Time-of-Flight Secondary Ion Mass Spectrometry with Microvolume Expansion Using Large Argon Clusters.

The molecular environment has an important impact on the ionization mechanism in time-of-flight secondary ion mass spectrometry (ToF-SIMS). In complex samples, desorption/ionization, and thus the detection of a molecular signal, can be hampered by molecular entanglement, ionization-suppressive neighbors, or even an unfavorable sample substrate. Here, a method called microvolume expansion is developed to overcome these negative effects. Large argon clusters are able to transfer biomolecules from a target to a collector in vacuum. In this study, argon gas cluster ion beams (Arn+-GCIB with n centered around 3000 or 5000) are used to expand a microvolume from the sample to a collector, which is a material ideally enhancing the ionization yield. The collector is then analyzed using a liquid metal ion gun. The signal amplification factor corresponding to the expansion of phosphatidylcholine (PC) lipid on collectors partially covered with acidic matrices was evaluated as an initial proof of concept. In one experiment, the PC expansion on a pattern of four drop-casted matrix-assisted laser desorption/ionization matrices led to the selection of α-cyano-4-hydroxycinnamic (CHCA) as the optimal candidate for cationic PC detection. The ion signal is increased by at least three orders of magnitude when PC was expanded using 10 keV Ar3000+ and Ar5000+ on a sublimated layer of CHCA. Finally, the expansion of the gray matter of a mouse on different materials (Si, Au-coated Si, CHCA, and polyethylene) was achieved with varying degrees of success, demonstrating the potential of the method to further analyze complex and fragile biological assemblies.

Comparing sputter rates, depth resolution, and ion yields for different gas cluster ion beams (GCIB): A practical guide to choosing the best GCIB for every application

Molecular gas species for gas cluster ion beams (GCIBs), such as carbon dioxide and water, were examined with a range of beam energies and cluster sizes to compare with the “universal relation” of the sputter yield, Y, per cluster atom against incident beam energy, E, per cluster atom of Arn cluster beam using Irganox 1010. In this work, we compare Arn, (CO2)n, and (H2O)n gas clusters to the universal equations for Arn clusters. To discuss molecular gas species for GCIBs, energy per nucleon (E/N) needs to replace energy per atom. We monitored sputter rate, depth resolution, and secondary ion yield as a function of the beam parameters: gas species, beam energy, and cluster size. (H2O)n GCIB shows reduced sputter rates and improved depth resolution with high sensitivity compared to Arn and (CO2)n GCIBs. These initial results indicate the potential to achieve high-depth resolution with high sensitivity and suggest that (H2O)n cluster ion beam has the potential to play a significant role in surface analysis techniques with organic materials. Results also show that no single set of conditions will provide the “best gas cluster ion beam” for all applications. However, it is possible to choose a set of conditions that will be more or less optimal depending on the experimental goals, such as maximizing the sputter rate, depth resolution, and molecular ion yield. In this work, we recommend the following three guidelines for GCIB users to set their own conditions: (1) to maximize the sputter rate, select a smaller cluster (higher E/N), but be aware that this will increase fragmentation and reduce molecular ion yield; (2) to maximize the depth resolution, select a larger cluster (lower E/N), and use (H2O)n GCIB, if possible; and (3) to maximize the molecular ion signal, use the highest beam energy available, and select a cluster with 0.15–0.25 eV/nucleon for Ar and (CO2)n GCIBs or around 0.1 eV/nucleon if using (H2O)n GCIB. These results are valid for XPS, SIMS, and any technique that utilizes GCIBs.