H2 System Research Articles

Computed Rotational Collision Rate Coefficients for Recently Detected Anionic Cyanopolyynes

We report new results from quantum calculations of energy-transfer processes taking place in interstellar environments and involving two newly observed molecular species: C5N− and C7N− in collision with He atoms and p–H2 molecules. These species are part of the anionic molecular chains labeled as cyanopolyynes, which have been observed over the years in molecule-rich circumstellar envelopes and in molecular clouds. In the present work, we first carry out new ab initio calculations for the C7N− interaction potential with He atoms and then obtain state-to-state rotationally inelastic cross sections and rate coefficients involving the same transitions, which have been observed experimentally by emission in the interstellar medium (ISM) from both of these linear species. For the C5N−/He system, we extend the calculations already published in Biwas et al. to compare more directly the two molecular anions. We extend further the quantum calculations by also computing in this work collision rate coefficients for the hydrogen molecule interacting with C5N−, using our previously computed interaction potential. Additionally, we obtain the same rate coefficients for the C7N−/H2 system by using a scaling procedure that makes use of the new C7N−/He rate coefficients, as discussed in detail in the present paper. Their significance in affecting internal state populations in ISM environments where the anionic cyanopolyynes have been found is analyzed by using the concept of critical density indicators. Finally, similarities and differences between such species and the comparative efficiency of their collision rate coefficients are discussed. These new calculations suggest that, at least for the case of these longer chains, the rotational populations could reach local thermal equilibrium conditions within their observational environments.

MICROFOCUSED ULTRASOUND FOR FACE LIFT

The evolution of technology in aesthetics and the concern to carry out less invasive procedures has given more and more space to procedures such as microfocused ultrasound. In this context, the main objective of this study was to evaluate the clinical efficacy of microfocused ultrasound for a facelift and its durability after months of application. Materials and methods: The procedure was carried out on 5 patients (N=5) in the middle/lower third of the face, and followed up for 4 months (120 days). Digital images of each subject were taken before and after treatment with the Vectra H2 system and after 4 months of the protocol. A questionnaire was administered among the patients involved in the study about their level of satisfaction with the procedure and among dental professionals who were not involved in the study, according to the GAIS scale. Results: A facelift was observed after 4 months in 100% of the cases and increased in 60% of the patients in the study. The majority of patients rated their satisfaction with the outcome of the treatment between number 2-(Improved a lot) (40%) and number 1-(Improved a lot) (40%). Around 20% rated their satisfaction with the procedure as number 3-(Improved), while in the blinded observers’ assessment, 80% rated the result as number 2-(Improved a lot) and 20% as number 1-(Improved a lot). There were no ratings of 4-(No improvement at all) or 5-(Worsened). Conclusion: The facelift obtained through microfocused ultrasound was maintained for four months after the procedure in all patients, when compared to stage 0 (before the protocol).

Experimental and numerical studies on the thermal nonequilibrium behaviors of CO with Ar, He, and H2

The time-dependent rotational and vibrational temperatures were measured to study the shock-heated thermal nonequilibrium behaviors of CO with Ar, He, and H2 as collision partners. Three interference-free transition lines in the fundamental vibrational band of CO were applied to the fast, in situ, and state-specific measurements. Vibrational relaxation times of CO were summarized over a temperature range of 1110–2820 K behind reflected shocks. The measured rotational temperature instantaneously reached an equilibrium state behind shock waves. The measured vibrational temperature experienced a relaxation process before reaching the equilibrium state. The measured vibrational temperature time histories were compared with predictions based on the Landau–Teller model and the state-to-state approach. The state-to-state approach treats the vibrational energy levels of CO as pseudo-species and accurately describes the detailed thermal nonequilibrium processes behind shock waves. The datasets of state-specific inelastic rate coefficients of CO–Ar, CO–He, CO–CO, and CO–H2 collisions were calculated in this study using the mixed quantum-classical method and the semiclassical forced harmonic oscillator model. The predictions based on the state-to-state approach agreed well with the measured data and nonequilibrium (non-Boltzmann) vibrational distributions were found in the post-shock regions, while the Landau–Teller model predicted slower vibrational temperature time histories than the measured data. Modifications were applied to the Millikan–White vibrational relaxation data of the CO–Ar and CO–H2 systems to improve the performance of the Landau–Teller model. In addition, the thermal nonequilibrium processes behind incident shocks, the acceleration effects of H2O on the relaxation process of CO, and the characterization of vibrational temperature were highlighted.

Electrification and hydrogenation on a PV-battery-hydrogen energy flexible community for carbon–neutral transformation with transient aging and collaboration operation

Considering the distinct differences in intrinsic characteristics (e.g., energy efficiency, power density, and response time), the synergy operation of combined hydrogen (H2) and battery systems within the source-grid-load-storage framework offers a promising solution to stabilize intermittent renewable energy supply, mitigate grid power fluctuations, and enhance system independence. However, the idling power of the H2 system (fuel cell and electrolyzer) poses significant limitations on H2 charging/discharging from intermittent renewable power sources, thereby affecting overall system performance. However, the current literature provides little progress on how to effectively self-consume onsite renewable energy and supply the electricity demand with high energy/power density in a fast response. To address these challenges, this study proposes and applies the H2-battery compensation operation in the hybrid H2-battery energy storage system to mitigate the adverse effects of idling power during low-carbon transformations. Additionally, transient degradation models for the battery and fuel cell (FC) are integrated into the system to dynamically quantify real-time aging, thereby avoiding performance overestimation. Moreover, the study also includes a comparative analysis of the pre-estimation on the H2 tank pressure level, and a parametrical analysis of the HV number and battery capacity. Results show that, compared to the isolated H2 energy storage system, the H2-battery synergy operation reduces the grid demand shortage coverage ratio from 91.01% to 57.8%. Furthermore, the proposed H2-battery compensation operation effectively overcomes the limitations of idling power during power charging/discharging of the H2 system, resulting in an increase of H2 demand shortage coverage ratio from 8.9% to 17.29%, and the decrease in battery degradation ratio from 1.73% to 1.65%. Afterward, a novel indicator, degradation cost per kWh energy, is proposed to quantify the techno-economic performance of the combined battery and H2 system. According to the results, the techno-economic feasibility is dependent on the proportion of battery and H2 capacities, with the FC ranging from 0.49 to 1.15 CNY/kWh and the battery ranging from 0.82 to 0.91 CNY/kWh. The research results provide valuable frontier guidelines for the design and operation of multi-energy systems, as well as innovative energy-sharing strategies, to achieve sustainable and carbon–neutral transformation.

Performance assessment of an energetically self-sufficient system for hydrogen production from oilfield wastewater treated by supercritical water gasification

Oilfield wastewater with high moisture content can be efficiently treated by supercritical water gasification (SCWG) technology to produce hydrogen. This paper conducted a thermodynamic and environmental analysis of the oilfield wastewater SCWG system to provide optimization strategies. The waste heat utilization technology can enhance the heat integration of the system to reduce the exergy destruction and increase the H2 yield. Sensitivity analysis showed that a ratio of preheating water to emulsion 3 can promote water-sensitive reactions to produce H2 and save the H2 needed to maintain the energetically self-sufficient system. Low system pressures, high feedstock preheating temperatures, and low oxidation reactor temperatures can reduce system energy destruction to obtain high H2 yield and system efficiency. Meantime, the developed SCWG system has the potential to achieve natural enrichment of greenhouse gases after the H2 separation has been completed. The use of waste heat utilization technology and carbon capture and storage (CCS) technology is expected to increase system efficiency to 53.43 % and reduce global warming potential (GWP) of 5.52 kg CO2-eq/kg H2. This work would be of great value to the process design and optimization for the SCWG system of oilfield wastewater.

Investigation of the Distribution of the Mass Transport and Reaction Rates in a Fuel Cell By the Integrated Fuel Cell System Simulator Including the Dynamics of Air, H2, and Cooling Systems

A 1+1D model to estimate the distribution of the mass transport and reaction rates in the through-plane and along-channel directions in a fuel cell (FC) was developed. The developed model was integrated to the FC system model and controllers which reproduce the dynamics of the 2nd-generation MIRAI, state-of-the-art fuel cell electric vehicle (FCEV). The dynamic behavior of the distribution of mass transport and reaction rates are investigated in low to high load and temperature conditions with the integrated simulator. It was shown that the H2O recirculation from the cathode outlet to inlet region inside the cell through the anode channel played an important role to the determination of the distribution. It was unique feature with the FC system without a humidifier in the air system and the counter-flow configuration of a fuel cell. The impacts of the specification of the controller in the H2 and air system on the overall system performance and the dynamic behavior of the distribution in a fuel cell. The increase of the anode inlet flowrate and cathode inlet pressure enhanced the H2O recirculation in the cell and improved the intensively nonuniform distribution of the humidity, which can cause the acceleration of mechanical degradation of the MEA. The tradeoff of the change of the controller specifications were assessed. It was demonstrated that the relationships among the specification of the controller, the overall system performance, and the dynamic behavior of the distribution in a fuel cell can be evaluated quantitatively.

2D-COFs-derived heteroatom-doped carbon nanosheets as high-efficiency all-solid frustrated lewis pair metal-free hydrogenation catalyst

Metal-free catalysts without metal active sites participating in the reactions have obtained growing attraction under the drive of the economic and environmental problems. Here, 2D-COFs-drived B/N co-doped carbon nanosheets as metal-free catalyst was synthesized by Schiff-based coupling reaction and self-templated carbonization. It shows excellent catalytic performance in nitro compound hydrogenation reaction as all-solid FLP catalyst in H2 system (100 % conversion of nitrobenzene and 99.89 % selectivity to aniline) without any metal active species in the catalyst. This result is the most promising compared to the previous literatures. In the study, the high crystallinity of precursor 2D-COFs is imperative for catalytic stability, and the function of B atoms modification and the B-N synergism were investigated carefully. The formation of B-N bond as a fixed all-solid FLP active center was verified, and it also indicates that B atoms introduction can make the carbon nanosheets orderly and enhance the strength and amount of the acid and base sites. The catalytic mechanism of hydrogen activation was also studied by combining the characterization results and density functional theory (DFT) calculations. The results show that the B atoms doping and defects formation efficiently accelerate the charges aggregation between B-N bonds to form Lewis pairs, and the TS searching calculations shows the significant decrease of H2 dissociation barrier energy and the reaction energy, demonstrating the effectiveness of N and B co-doping strategy. This work is very promising and the metal-free catalyst is the potential alternative to traditional metal catalysts.

An improved artificial neural network fit of the ab initio potential energy surface points for HeH+ + H2 and its ensuing rigid rotors quantum dynamics

Artificial neural networks (ANN) have been shown for the last several years to be a versatile tool for fitting ab initio potential energy surfaces. We have demonstrated recently how a 60-neuron ANN could successfully fit a four-dimensional ab initio potential energy surface for the rigid rotor HeH+ - rigid rotor H2 system with a root-mean-squared deviation (RMSD) of 35 cm−1. We show in the present study how a (40, 40) neural network with two hidden layers could achieve a better fit with an RMSD of 5 cm−1. Through a follow-up quantum dynamical study of HeH+(j1)-H2(j2) collisions, it is shown that the two fits lead to slightly different rotational excitation and de-excitation cross sections but are comparable to each other in terms of magnitude and dependence on the relative translational energy of the collision partners. When averaged over relative translational energy, the two sets of results lead to rate coefficients that are nearly indistinguishable at higher temperatures thus demonstrating the reliability of the ANN method for fitting ab initio potential energy surfaces. On the other hand, we also find that the de-excitation rate coefficients obtained using the two different ANN fits differ significantly from each other at low temperatures. The consequences of these findings are discussed in our conclusions.

SOME FEATURES OF THE PROCESS OF INTERACTION OF IRON WITH METHANE AT A TEMPERATURE OF 900°C AND A PRESSURE OF 100 MPA

Using the original high-gas pressure unit (IHPV), experiments were conducted for the first time on the interaction of iron with methane at a temperature of 900°C and a pressure of 100 MPa. Complex methods (microprobe, Raman spectroscopy, chromatography, mass balance calculations) are used for a thorough analysis of fluid compositions and metallic phases formed in experiments. For the first time, experimental and theoretical quantitative data on the composition of the fluid and the composition of the fluid components dissolved in the metal were obtained. Unlike the previously studied Fe3C–H2 system, in experiments, when Fe reacts with methane, there is an active interaction of carbon formed due to the pyrolysis of methane with iron up to the synthesis of Fe3C carbide. The experiments have shown that increasing pressure inhibits significantly hydrogen yield during methane conversion on metallic iron. Carbon saturation of iron with the formation of Fe3C is not complete within the entire volume of the metal during 24 h runs at 900°С. Employing molybdenum containers facilitates CH4 decomposition.

Integrating Enrichment, Reduction, and Oxidation Sites in One System for Artificial Photosynthetic Diluted CO2 Reduction.

Artificial photosynthetic diluted CO2 reduction directly driven by natural sunlight is a challenging, but promising way to realize carbon-resources recycling utilization. Herein, a three-in-one photocatalytic system of CO2 enrichment, CO2 reduction and H2 O oxidation sites is designed for diluted CO2 reduction. A Zn-Salen-based covalent organic framework (Zn-S-COF) with oxidation and reductive sites is synthesized; then, ionic liquids (ILs) are loaded into the pores. As a result, [Emim]BF4 @Zn-S-COF shows a visible-light-driven CO2 -to-CO conversion rate of 105.88µmol g-1 h-1 under diluted CO2 (15%) atmosphere, even superior than most photocatalysts in high concentrations CO2 . Moreover, natural sunlight driven diluted CO2 reduction rate also reaches 126.51µmol g-1 in 5h. Further experiments and theoretical calculations reveal that the triazine ring in the Zn-S-COF promotes the activity of H2 O oxidation and CO2 reduction sites, and the loaded ILs provide an enriched CO2 atmosphere, realizing the efficient photocatalytic activity in diluted CO2 reduction.

Estimation of Mastectomy Volume Using Preoperative Mastectomy Simulation Images Acquired by the Vectra H2 System.

All patients underwent skin-sparing mastectomy and immediate autologous breast reconstruction. Preoperatively, the patient's breast was scanned using the Vectra H2 and a postmastectomy simulation image was constructed on a personal computer. The estimated mastectomy volume was calculated by comparing the preoperative and postmastectomy three-dimensional simulation images. Correlation coefficients with the estimated mastectomy volume were calculated for the actual mastectomy weight and the transplanted flap weight. Forty-five breasts of 42 patients were prospectively analyzed. The correlations with the estimated mastectomy volume were r = 0.95 (P < 0.0001) for actual mastectomy weight and r = 0.84 (P < 0.0001) for transplanted free-flap weight. The mastectomy weight estimation formula obtained by linear regression analysis using the estimated mastectomy volume was 0.98 × estimated mastectomy volume + 5.4 (coefficient of determination R2 = 0.90, P < 0.0001). The root-mean-square error for the mastectomy weight estimation formula was 38 g. We used the Vectra H2 system to predict mastectomy volume. The predictions provided by this method were highly accurate. Three-dimensional imaging is a noncontact, noninvasive measurement method that is both accurate and simple to perform. Use of this effective tool for volume prediction is expected to increase in the future.

Some Features of the Process of Interaction of Iron with Methane at a Temperature of 900°C and a Pressure of 100 MPa

Using the original high-gas pressure unit (IHPV), experiments were conducted for the first time on the interaction of iron with methane at a temperature of 900°C and a pressure of 100 MPa. Complex methods (microprobe, Raman spectroscopy, chromatography, mass balance calculations) are used for a thorough analysis of fluid compositions and metallic phases formed in experiments. For the first time, experimental and theoretical quantitative data on the composition of the fluid and the composition of the fluid components dissolved in the metal were obtained. Unlike the previously studied Fe3C–H2 system, in experiments, when Fe reacts with methane, there is an active interaction of carbon formed due to the pyrolysis of methane with iron up to the synthesis of Fe3C carbide. The experiments have shown that increasing pressure inhibits significantly hydrogen yield during methane conversion on metallic iron. Carbon saturation of iron with the formation of Fe3C is not complete within the entire volume of the metal during 24 h runs at 900°С. Employing molybdenum containers facilitates CH4 decomposition.

Molecular data needs for advanced collisional-radiative modelling for hydrogen plasmas

Population models for molecular hydrogen (H2) are applicable in various fields of plasma physics and particularly in fusion research: they are necessary for the evaluation of plasma diagnostics (e.g. optical emission spectroscopy) or can be used to evaluate effective reaction rates for molecular processes (e.g. molecular-assisted recombination in divertor plasmas). The accuracy and completeness of population models for molecular hydrogen is strongly linked to the accuracy and availability of molecular reaction data. While there are recently huge improvements in the field of electron impact cross sections, the shortfalls regarding input data availability persist in the area of collisions between heavy particles and H2. An overview of the status of population models for H and H2 based on the Yacora solver is given. The data needs for collisional-radiative modelling are demonstrated by means of three examples comprising different detail levels, namely a purely electronic collisional-radiative model for the singlet system of H2, a corona model for the Fulcher-α band and a vibrationally resolved collisional-radiative model for the electronic ground state X1 of H2.Graphical abstractElectronic energy level diagram of the hydrogen molecule delimiting the population models discussed in this work

Build more and regret less: Oversizing H2 and CCS pipeline systems under uncertainty

The large-scale deployments of Carbon Capture and Storage (CCS) and hydrogen (H2) require the installation of costly carbon dioxide (CO2) and H2 pipeline infrastructures. As the future demands for CO2 and H2 pipeline transportation are expected to increase substantially, this paper examines the economics of installing adequately oversized infrastructures. We analytically show that the underlying engineering equations de facto define Cobb-Douglas production functions for both fluids. We then use these production functions to determine the cost-minimizing decisions of a pipeline operator and infer the optimal ratio of oversizing. From a policymaking perspective, this ratio indicates whether the level of oversizing envisioned by the operator is consistent with its expectations of future demand (and thus, by contrast, whether it is attempting to overcapitalize and exploit a regulatory flaw). As the anticipations of the operator may fail to materialize, we opt for a minimax regret perspective and compare the performances of the operator's investment decisions under alternative demand trajectories. Our study shows that the conservative recommendation to build for the proven demand only is systematically regret-maximizing. Consequently, an infrastructure push would likely contribute to overcoming the chicken and egg problem and thus support the large-scale deployment of these emerging technologies.

Adsorption on 3C-SiC surfaces in chemical vapor deposition process of CH3SiCl3–H2 system: a first-principles study

SiC has become increasingly important in high-energy semiconductor device materials and structural composite materials in recent years. Many systematic experimental studies have been conducted on the preparation of cubic silicon carbide (3C-SiC) by the chemical vapor deposition (CVD) process. Despite this, the microscopic mechanism of the SiC deposition process has not been fully elucidated due to the limitations of the experimental methods. Based on these problems, the structural parameters, adsorption energies, charge populations, transition states, and electronic densities of states of Si-Cl-C-H at different sites were simulated by a first-principles method, and the micro-mechanism of the surface deposition reaction was analyzed. The calculated results provide a theoretical and experimental basis for the study of 3C-SiC preparation by CVD.

Adsorption and sensing of dissolved gas molecules in transformer oil on Rh-doped MoTe2 monolayer: A first-principles study

Oil-immersed transformer plays a significant role in power systems, whose insulation failure will threaten the stable operation of the system, thus the requirements for its operational stability are higher. In this paper, the Rh-doped MoTe2 (Rh-MoTe2) monolayer is proposed for the detection of several typically dissolved gas molecules (CO, H2 and CH4) based on the first-principles density functional theory (DFT). It is found that the Rh dopant preferred to be adsorbed through the TMo site with maximum binding energy (Eb) of −3.43 eV. Then, the adsorption of Rh-MoTe2 on CO, H2 and CH4 molecules is investigated with adsorption energy (Ead). Furthermore, the band gaps of CO and H2 systems have significantly reduced, showing their excellent potential as resistance-type gas sensors; while CH4 is not suitable for detection due to the weak interaction. This study illustrates the physicochemical properties of Rh-MoTe2 monolayer and reveals its promising applications in dissolved gas analysis (DGA).

Effect of confinement and external mechanical force on the cleavage of the bond in a diatomic molecule

Mechanochemical synthesis has gained much attention owing to its environment-friendly nature. The application of mechanical force on the reactants changes the reactivity of the chemical systems and the reactivity of the chemical entities can be changed by altering its surrounding, like encapsulating the chemical entities inside a cavity. The effect of confinement and mechanical stretching force on the nature of the bond in the diatomic systems has been extensively studied using theoretical models. The diatomic systems that have been considered are F2, H2, O2, N2, ClBr, NaCl, CO, LiF and HCl and the confinement being used is that of fullerene cage C60. It has been found that the confinement strengthens the diatomic bond for ClBr, NaCl, N2 and H2 systems whereas for some other systems, the bond strength decreases. The possible reason behind such observation has been explored with the help of Natural Bond Orbital (NBO) analysis, Atoms in Molecules (AIM) analysis and Energy Decomposition Analysis (EDA). The reactivity change with respect to the external mechanical stretching force has been studied and the presence of non-covalent interaction (NCI) is visualised through NCI plots. The dynamics of the systems have also been explored using Atom Centred Density Matrix propagation (ADMP) simulation.

CFD simulation of CVD reactors in the CH3SiCl3(MTS)/H2 system using a two-step MTS decomposition and one-step SiC growth models

In this study, we report on a computational fluid dynamics (CFD) simulation of the chemical vapor deposition reactor of silicon carbide (SiC) in the methyltrichlorosilane (MTS, CH3SiCl3)/H2 system. The formation of SiC thin film is controlled by various process parameters, such as temperature and pressure. In this study, we propose a reaction mechanism of MTS decomposition to SiC growth on a substrate surface for CVD reactors in the CH3SiCl3(MTS)/H2 system. The reaction mechanism has two gas-phase pyrolysis reactions and one SiC film formation reaction. However, we individually build and validate MTS decomposition and SiC growth models to reduce uncertainty. An in-house version of reactingFoam, a reactive flow solver within OpenFOAM v2006, was used as the simulation tool. Our model accurately reproduced MTS decomposition for T = 1100–1350 K and [H2]/[MTS] = 2.65–14 at p = 101,325 Pa. Then, the MTS decomposition model was coupled with the SiC growth model, and the coupled model was applied to the SiC deposition data. The model could reproduce multiple datasets through validation studies.

Identification and synergetic mechanism of TCE, H2 and O2 metabolic microorganisms in the joint H2/O2 system

The sole H2 and O2 usually promote chlorinated hydrocarbons (CHCs) biotransformation by several mechanisms, including reductive dechlorination and aerobic oxidation. However, the mechanism of the CHCs transformation in joint H2 and O2 system (H2/O2 system) is still unclear. In this study, the degradation kinetics of trichloroethene (TCE) were investigated and DNA stable isotope probing (DNA-SIP) were used to explore the synergistic mechanism of functional microorganisms on TCE degradation under the condition of H2/O2 coexistence. In the H2/O2 microcosm, TCE was significantly removed by 13.00 μM within 40 days, much higher than N2, H2 and O2 microcosms, and 1,1-DCE was detected as an intermediate. DNA-SIP technology identified three anaerobic TCE metabolizers, five aerobic TCE metabolizers, nine hydrogen-oxidizing bacteria (HOB), some TCE metabolizers utilizing limited O2, and some anaerobic dechlorinating bacteria reductively using H2 to dechlorinate TCE. It is also confirmed for the first time that 3 OUTs belonging to Methyloversatilis and SH-PL14 can simultaneously utilize H2 and O2 as energy sources to grow and metabolize TCE or 1,1-DCE. HOB may provide carbon sources or electron acceptors or donors for TCE biotransformation. These findings confirm the coexistence of anaerobic and aerobic TCE metabolizers and degraders, which synergistically promoted the conversion of TCE in the joint H2/O2 system. Our results provide more information about the functional microbe resources and synergetic mechanisms for TCE degradation.

Cold Collisions of Ro-Vibrationally Excited D2 Molecules.

The H2 + H2 system has long been considered a benchmark system for ro-vibrational energy transfer in bimolecular collisions. However, most studies thus far have focused on collisions involving H2 molecules in the ground vibrational level or in the first excited vibrational state. While H2 + H2/HD collisions have received wide attention due to the important role they play in astrophysics, D2 + D2 collisions have received much less attention. Recently, Zhou et al. [ Nat. Chem. 2022, 14, 658-663, DOI: 10.1038/s41557-022-00926-z] examined stereodynamic aspects of rotational energy transfer in collisions of two aligned D2 molecules prepared in the v = 2 vibrational level and j = 2 rotational level. Here, we report quantum calculations of rotational and vibrational energy transfer in collisions of two D2 molecules prepared in vibrational levels up to v = 2 and identify key resonance features that contribute to the angular distribution in the experimental results of Zhou et al. The quantum scattering calculations were performed in full dimensionality and using the rigid-rotor approximation using a recently developed highly accurate six-dimensional potential energy surface for the H4 system that allows descriptions of collisions involving highly vibrationally excited H2 and its isotopologues.