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This study demonstrates the charge additivity of core valence metal ions with fixed ionic pendant groups can significantly boost the thermoelectrochemical valorisation of waste heat into electricity, but is solvent-specific.

We report a facile and low temperature synthesis of Ga- and In-doped CdS nanoparticles from molecular precursors. Diethyldithiocarbamate complexes of Cd(ii), Ga(iii), and In(iii), were synthesised and decomposed in tandem through solventless thermolysis, producing Ga- or In-doped CdS. The resultant M xCd 1−xS 1+0.5x (where M = Ga/In at x values of 0, 0.02, 0.04, 0.06, 0.08 and 0.1) particulate powder was analysed by powder X-ray diffraction, which showed that both Ga (through all doping levels) and In (at doping levels xCd 1−xS 1+0.5x materials were examined by UV-Vis absorption and photoluminescence spectroscopies respectively. All materials were found to exhibit excitonic emission, corresponding to band gap energies between 2.7 and 2.9 eV and surface defect induced emission which is more prominent for Ga than for In doping. Additionally, moderate doping slows down charge carrier recombination by increasing the lifetimes of excitonic and surface state emissions, but particularly for the latter process.

Metal oxides, sulphides, selenides and tellurides have routinely been investigated and utilised for a wide range of applications, in particular in the areas of energy (photovoltaic, thermoelectric) and catalysis (thermocatalysis, electrocatalysis and photoelectrocatalysis). A recent development in this chemical space is high entropy and entropy-stabilised inorganic materials, which took inspiration from preceding work on high entropy metal alloys (multicomponent alloys). High entropy inorganic materials typically have many (often ≥6) different cations or anions to yield a high configurational entropy, which can give unexpected structures and properties that are conducive to a broad range of applications in energy and catalysis. More recently still, high entropy metal chalcogenides have been developed and have been investigated for thermoelectric energy generation, batteries for energy storage and electrocatalysis. This review sets out to define entropic stabilisation in high entropy materials, along with a discussion of synthetic techniques to produce these compounds, focusing on high entropy metal chalcogenides including extant routes to high entropy sulfides, selenides and tellurides. The resulting advantageous properties of these materials due to their multi-element nature and the currently proposed and investigated applications of these materials are reviewed. We end the perspective with an opinion on future directions.

Copper(I) oxide (Cu2O) nanomaterials have become highly promising for photoelectrochemical reactionsas both solar absorber layers in p–n heterojunction solar cells, direct photoelectrocatalysis and as electrodes in the CO2 reduction reaction. Here we undertake a synthetic study towards the synthesis ofCu2O nanocubes by utilising electrodeposition from copper salts (chloride, acetate, nitrate, and sulphate)in different solution environments. We initially set out to investigate the effect of electrolyte concentration on the growth of Cu2O nanocubes. We also set out to mimic the high resistance inherent in thelow electrolyte concentration environment by altering the distance between the electrodes. This deposition method was found to enable control of nanocube size formation. Both mixed anion environmentsand mono-anion environments were also investigated in a low-electrolyte concentration system. Thefundamental physiochemical and electrochemical properties of each solution such as pH, conductivity,open circuit potential (VOCP), solution resistance (RS), and electron transfer resistance (RET) were measured.We then deposited copper oxide nanomaterials as thin films on ITO-coated glass substrates and assessedthe electrical (conductivity) and optical (UV-Vis and Eg) properties of these films. Finally, we set out toinvestigate if any possible correlations could be drawn between the physiochemical and electrochemicalproperties of the solution and the electronic and optical properties of the deposited Cu2O thin films

Ionic rectifier membranes or devices generate uni-directional ion transport to convert an alternating current (AC) ion current input into stored energy or direct current (DC) in the form of ion/salt gradients. Electrochemical experiments 80 years ago were conducted on biological membrane rectifier systems, but today a plethora of artificial ionic rectifier types has been developed and electroanalytical tools are employed to explore mechanisms and performance. This overview focuses on microscale ionic rectifiers with a comparison to nano- and macroscale ionic rectifiers. The potential is surveyed for applications in electrochemical analysis, desalination, energy harvesting, electrochemical synthesis, and in selective ion extraction.

Cadmium sulfide (CdS) is an important semiconductor for electronic and photovoltaic applications, particularly when utilised as a thin film for window layers in CdTe solar cells. Deposition of thin film CdS through the decomposition of single source precursors is an attractive approach due to the facile, low-temperature and rapid nature of this approach. Tailoring the precursor to affect the decomposition properties is commonly employed to tune desirable temperatures of decomposition. However, altering the precursor structure and the effect this has on the nature of the deposited material is an area far less commonly investigated. Here we seek to investigate this by altering the ligands around the Cd metal centre to increase the steric hinderance of the precursor and investigate the effect this has on the decomposition properties and the properties of deposited thin film CdS from these precursors. For this, we report the synthesis of four CdS precursors with xanthate and pyridyl ligands ([Cd(n-ethylxanthate)2(3-methylpyridine)2] [1], [Cd(n-ethylxanthate)2(3,5-lutidine)2] [2], [(Cd2(isopropylxanthate)4(3-methylpyridine)2)n] [3], [Cd(isopropylxanthate)2(3,5-lutidine)2] [4]). These single source precursors for CdS were fully characterised by elemental analysis, NMR spectroscopy, single crystal XRD and thermogravimetric analysis. It was found that even with subtle alterations in the xanthate (n-ethyl to isopropyl) and pyridine (3-methyl and 3,5-dimethyl) ligands, a range of hexa-coordinate precursors were formed (two with cis configuration, one with trans configuration and one as a 1D polymer). These four precursors were then used in AACVD and spin coating experiments to deposit eight thin films of CdS, which were characterised by Raman spectroscopy, powder x-ray diffraction and scanning electron microscopy. Comparative quantitative information concerning film thickness and surface roughness was also determined by atomic force microscopy. Finally, the optical properties of all thin films were characterised by UV-Vis absorption spectroscopy, from which the band gap of each deposited film was determined to be commensurate with that for bulk CdS (ca. 2.4 eV).

Thermogalvanic devices can harvest wasted thermal energy; a waste product that is generated by humanity in staggering abundance. However, the incorporation of thermogalvanic devices in applications from hot, industrial environments through to waste body heat harvesting necessitates safe chemicals. In particular, since the redox active ions are the charge carriers the chemistry of these is crucial; the bigger and more powerful the device, the greater the abundance of these chemicals. The anionic ferricyanide/ferrocyanide ([Fe(CN)6]3−/4−) redox couple is arguably the most widely utilised and investigated thermogalvanic electrolyte, but has inherent (in)stability issues, and therefore safety issues. This study has investigated a wide range of anionic polycarboxylate and polyaminocarboxylate ligands in conjunction with iron(II/III) chloride (FeCl2/3) in an effort to develop a safer [Fe(CN)6]3−/4−-replacement. Detailed electrochemical and spectroscopic characterisation was used across the wide range of ligands investigated, and several were found to be viable for use in thermogalvanic cells. In particular, optimised nitriloacetic acid was found to yield a redox-active complex, [Fe(NTA)2]3−/4−, with a good Seebeck coefficient (−1.35 mV K−1) on par with [Fe(CN)6]3−/4−. However, diethylenetriaminepentaacetic acid (to form [Fe(DEPTA)]2−/3−) demonstrated the optimum compromise between thermodynamic and kinetic properties; this was used to prepare an in-series thermogalvanic device with the parent Fe2+/3+ species. Benchmarking against relative costs, and the principles of green chemistry and green chemical engineering was used to identify the relative merits of the different systems.

Background: Patient-centered care is strongly advocated as a key for improving the quality of healthcare. Research examining the impact of patient-centered care in healthcare has concluded that there are demonstrable albeit inconsistent relationships between patient experience, quality of care, and healthcare outcomes. Knowledge of the impact of patient-centered care in the treatment of substance use disorder is limited. The aim of this review was to assess relationships between indicators of patient-centered care (satisfaction and patient-reported experience measures) and patient outcomes (substance use, psychological wellbeing, and service use) among people attending treatment for substance use disorder. Methods: A systematic electronic literature search of a range of databases was conducted with variations of the search terms ‘patient-centered care’, ‘substance use disorders’, and residential or community specialist ‘treatment’. The populations, interventions and outcomes were summarized and described according to the PRISMA statement. Results: A total of 25 articles were identified, of which only five included a patient-centered indicator other than satisfaction. Indicators of patient-centered care showed a generally positive association with improved outcomes, particularly between satisfaction with treatment and substance use. Nonetheless, mixed and contradictory results were not uncommon, more so for psychological wellbeing outcomes. Conclusions: There were demonstrable relationships between patient-centered indicators and outcomes for people receiving treatment for substance use disorder. However, conclusions are limited due to underrepresentation of patient-reported experience measures. Further research in the area is needed involving comparisons of patient centered indicators with outcomes and use of patient-reported experience measures together with satisfaction. Registration number: CRD42018092829

The first page of this article is displayed as the abstract.

Harvesting wasted thermal energy could make important contributions to global energy sustainability. Thermogalvanic devices are simple, chemistry-based devices which can convert heat to electricity, through facile redox chemistry. The efficiency of this process is the ratio of electrical energy generated by the cell (in Watts) to the quantity of thermal energy that passes through the cell (also in Watts). Prior work estimated the quantity of thermal energy passed through a thermocell by applying a conductive heat transfer model to the electrolyte. Here, we employ a heat flux sensor to unambiguously quantify both heat flux and electrical power. By evaluating the effect of electrode separation, temperature difference and gelation of the electrolyte, we found significant discrepancy between the estimated model and the quantified reality. For electrode separation, the trend between estimated and measured efficiency went in opposite directions; as a function of temperature difference, they demonstrated the same trend, but estimated values were significantly higher. This was due to significant additional convection and radiation contributions to the heat flux. Conversely, gelled electrolytes were able to suppress heat flux mechanisms and achieve experimentally determined efficiency values in excess of the estimated values (at small electrode separations), with partially gelled systems being particularly effective. This study provides the ability to unambiguously benchmark and assess the absolute efficiency and Carnot efficiency of thermogalvanic electrolytes and even the whole thermocell device, allowing 'total device efficiency' to be quantified. The deviation between the routinely applied estimation methodology and actual measurement will support the rational development of novel thermal energy harvesting chemistries, materials and devices.

Thermogalvanic cells typically utilise equimolar concentrations of the oxidised and reduced states of a redox couple in solution, sandwiched between two electrodes at dissimilar temperatures; entropy drives redox processes to occur at these electrodes, generating a potential difference and a current. However, significant gaps still exist in fundamental data and understanding of these ‘thermocells’. In this study, thermocells based upon potassium ferricyanide, K3[Fe(CN)6], and potassium ferrocyanide, K4[Fe(CN)6], were investigated. The ratio of the oxidised and reduced states were systematically varied, and this had a significant effect upon the power produced; notably maximum power did not correspond to the equimolar ratio. A concentration study using equimolar ratios was also performed. Trends in the potential generated as a function of temperature (or ‘Seebeck coefficient’) were rationalised by the Nernst equation and Debye–Huckel theory. The trends in the current and the electrical power produced were successfully modelled using the Butler–Volmer equation. The effects of heterogeneous electrocatalysis were also explored (using platinum and two types of graphite) as well as homogeneous electrocatalysis, by the direct addition of alkali metal salts (as lithium, sodium, potassium, rubidium and caesium chlorides and sulphates). Clear trends were observed, and homogeneous and heterogeneous electrocatalysis had an additive effect when combined. Addition of CsCl was able to boost the maximum power output by upto ca. 80%, via both an increased Seebeck coefficient (through altered solvation) and through increased current (via homogeneous electrocatalysis of electron transfer). Finally, a limited economic comparison was performed, which highlights how the use of non-stoichiometric ratios of the redox couple could improve the cost-per-power value of the systems.

Two methods are reported for the one-pot preparation of high concentrations of gold nanoparticles (AuNPs) embedded throughout sodium polyacrylate hydrogels; this stabilises the AuNP in even extremely high ionic strength environments, and enables them to act as effective catalysts for the hydride-reduction of nitrophenols and of dyes, with zero order kinetics.

Thermogalvanic cells can act like ‘liquid thermoelectrics’ to convert a thermal energy gradient to electrical energy. Such cells are typically combined electrically in-series in devices to boost the output voltage (as thermocells). However, the typical system involves a potentially fatal combination of inherently acidic or acidified Fe2+/3+ and [Fe(CN)6]3−/4− electrolytes; mixing and heating is expected to trigger extremely toxic HCN gas release. Here we demonstrate that benign aqueous iron(II/III) sulphate can be combined with equally benign sodium sulphate and sodium hydrogen sulphate; the first leads to an [Fe(SO4)2]−/2− thermocell (Seebeck coefficient, Se = −0.4 mV K−1), and the second to a thermocell with intermediate [FeSO4]0/+ and [Fe(HSO4)]+/2+ character (Se = +0.57 mV K−1). Their fundamental thermoelectrochemistry was explored, and their speciation elucidated. It was demonstrated that these can be utilised electrically in-parallel and in-series in thermogalvanic devices. When connected electrically in-series the thermocells presented here displayed temperature-dependent open circuit potentials only ca. one-third that typically reported for the ‘conventional’ combination of Fe2+/3+- and [Fe(CN)6]3−/4−-based thermocells (0.8 mV K−1vs. ca. 3 mV K−1, respectively). However, whereas the latter thermocells cannot be safely mixed, when the iron-sulphate cells were ‘accidently’ mixed they safely form a mixed thermocell electrolyte (Se = +0.19 mV K−1), enabling a ‘second life’ of both the electrolyte and thermocell devices. This novel ‘all-iron sulphate’ thermocell was compared against the typically employed Fe2+/3+ and [Fe(CN)6]3−/4− combination using the 12 principles of green chemistry and of green engineering, further demonstrating the inherent sustainability, safety and ‘green’ credentials of this system (but not yet efficiency). This work demonstrates how functionality and complexity can be introduced in a safe manner, while also preventing potential accidents and enabling new ‘end-of-life’ opportunities.

Background Client centered care is strongly advocated as key to improving the quality of health care. However, there is a notable absence of research about the acceptability and feasibility of a client centered approach in substance dependence treatment settings. The aim of this study was to explore client and staff perspectives of a new client centered model of care implemented at Kedesh Rehabilitation Services, a residential substance dependence treatment service.Methods Participants were client and staff at Kedesh between April 2018 and April 2019. Clients were invited to take part in a focus group and staff in individual interviews. Questions elicited client and staff experience of client centered care at Kedesh, including advantages and disadvantages. Staff were also asked to describe how they would define the client centered model. Thematic analysis was conducted on transcriptions of audio recordings.Results Four focus groups were conducted amongst 18 clients and 8 individual interviews amongst staff. Staff identified the defining features of client centered care as that which is flexible, comprehensive, open-minded and inclusive. Clients and staff shared predominantly positive views on the client centered model, with an emphasis on the satisfaction in providing and receiving what felt like more authentic and comprehensive care. Shared themes emerged for clients and staff on the challenge of striking a balance between flexibility and structure, and managing comprehensive and individualized care within existing knowledge, skills and resources.Conclusions Client centered care encourages health care organisations and providers to strive for a more holistic and empowering standard of care. Results support the acceptability of client centered care in residential substance dependence treatment settings for both clients and staff. Future research is needed to develop knowledge in interpreting, implementing, and assessing client centered care in the treatment of substance dependence.

Thermogalvanic conversion of temperature gradients into electricity via a redox couple represents a potential method of waste energy harvesting, but inexpensive, effective and sustainable redox couples are required. In this study four aqueous Fe(II)/Fe(III) salt systems are considered, based upon ammonium iron sulphate, iron sulphate, iron trifluoromethanesulfonate and iron nitrate. A range of Seebeck coefficients were observed, from +0.18 ± 0.04 mV K−1 for ammonium iron(II/III) sulphate to +1.46 ± 0.02 mV K−1 for acidified iron(II/III) trifluoromethanesulfonate, both at a temperature difference of 20 K; notably these apparent Seebeck coefficients vary with temperature difference due to significant chemical equilibria. The iron(II/III) nitrate system generated the highest thermogalvanic power output. The systems were probed by cyclic voltammetry, pH, UV-Vis spectroscopy and electrochemical impedance spectroscopy, and two competing mechanisms noted, which strongly affect both the current output and Seebeck coefficient (i.e. potential output) of their thermoelectrochemical cells (or thermocells). Green and economic consideration are important aspects if these systems are to be employed in harvesting low-grade heat energy at a larger scale; iron nitrate and acidified iron sulphate were the most highly competitive systems.

Summary The majority of usable energy generated by humanity is lost as waste heat, but thermogalvanic systems (or thermocells) can address this problem by converting low-grade waste heat directly into electricity using redox chemistry. The concentration of the redox couple is a critical parameter; almost invariably, higher concentrations result in more power. This study exploits the simple synergy between Na+ and K+ counter ions to achieve—to the best of our knowledge—the most concentrated stable aqueous ferricyanide/ferrocyanide thermocell to date, at 1.6 m [Fe(CN)6]3−/4−. Despite increasing the concentration by 400% relative to the standard K3/K4[Fe(CN)6] electrolyte (0.4 m), electrical power production increased only 166%. Pushing the system from conventional salt-in-water electrolytes into the quasi-stable water-in-salt region (up to 2.4 m) resulted in a decrease in power. Detailed characterization highlighted the various physicochemical hurdles introduced by these extremely concentrated electrolytes; the identified issues have direct relevance to other energy systems also seeking to use the highest possible concentration.

Bis-3-methylpyridine and bis-4-methylpyridine complexes of cadmium(II) ethylxanthate have been characterized by elemental analysis, NMR spectroscopy, and thermogravimetric analysis. The single crystal X-ray structures of both methylpyridine derivatives have also been determined and shown to display a cis, cis, cis-configuration of the N- and S-donor ligands. The compounds have been utilized as single source precursors to deposit CdS films on silica-coated glass substrates at 220 and 350 °C by aerosol-assisted chemical vapor deposition. The surface morphology of the films has been examined by scanning electron microscopy analysis and the crystalline phases were studied by powder X-ray diffraction. The films deposited from the 3-methylpyridine adduct comprised more densely packed and more highly crystalline hexagonal CdS than those provided by either of the other two precursors. The crystallite sizes were found to be

Thermoelectrochemical cells (thermocells) designed for harvesting human body heat can provide constant power output for wearable electronics, supplementing state‐of‐the‐art flexible power storage and conversion solutions. However, a systematic investigation into the optimization of wearable thermocells is lacking, especially with regard to device design, n‐type electrolytes, and electrode/electrolyte integration. Here, a n‐type gel electrolyte: polyvinyl alcohol‐FeCl2/3 with outstanding flexibility and elasticity and exceptional electrolyte/electrode integration into a 3D porous poly(3,4‐ethylenedioxythiophene)/polystyrenesulfonate (PEDOT/PSS) electrode, is produced via an in situ chemical crosslinking method. The integrated n‐type cell shows excellent seebeck coefficients (0.85 mV K−1) and output current density (1.74 A m−2 K−1) that are comparable with an optimized p‐type cell consisting of a carboxymethylcellulose‐K3/4Fe(CN)6 electrolyte with a 3D PEDOT/PSS‐edge functionalized graphene/carbon nanotube electrode (−1.22 mV K−1 and 1.85 A m−2 K−1). The equivalent performance of the n‐type and p‐type cells enables the effective series connection of up to 18 pairs of p–n cells that combines to give an output voltage of 0.34 V (∆T = 10 K). This in‐series device is fabricated into a proof‐of‐concept watch strap, which can harvest body heat, charge supercapacitor (up to 470 mF) as well as illuminate a green light emitting diode, demonstrating the practical applications.

Thermogalvanic cells (or thermocells) are being increasingly investigated due to their ability to directly convert modest temperature gradients into electricity, using redox chemistry. However, this has resulted in a diverse range of cells, electrolytes, temperature gradients, etc. being reported. Recently, so-called temperature-difference ‘normalised’ power outputs have been reported; the power output is divided by the square of the temperature difference to yield temperature-insensitive power output values. The validity of this procedure is quantitatively assessed here, and found to be far from accurate. Additionally, numerous different experimental procedures for measuring the current and power output from thermocells can be found in the literature, covering different approaches, vastly different time scales, and employing a diverse range of measuring instruments. A range of experimental methodologies covering a sequence of constant resistances (or resistive loads), a sequence of constant currents, a sequence of constant potentials (or voltage), chronoamperometry and linear sweep voltammetry (LSV) were evaluated in this study, using source measure units, potentiostats and voltammeters/multimeters. While most methodologies were consistent, the measurement time and number of electrodes were found to be highly influential, with LSV and 3-electrode assemblies especially overestimating the current and power output from thermocells.

The radical redox mediator tetrachloro-phthalimido-N-oxyl (Cl4PINO) is generated at a glassy carbon electrode and investigated for the model oxidation of primary and secondary alcohols with particular attention to reaction rates and mechanism. The two-electron oxidation reactions of a range of primary, secondary, and cyclic alcohols are dissected into an initial step based on C-H hydrogen abstraction (rate constant k1, confirmed by kinetic isotope effect) and a fast radical-radical coupling of the resulting alcohol radical with Cl4PINO to give a ketal that only slowly releases the aldehyde/ketone and redox mediator precursor back into solution (rate constant k2). In situ electrochemical EPR reveals Cl4PINO sensitivity towards moisture. DFT methods are applied to confirm and predict C-H hydrogen abstraction reactivity.

A repeated measures design was used to evaluate a 12 month on-site counsellor internship programme aimed at training staff to support the recovery needs of people with co-occurring substance use and mental health disorders. Fifty-four interns completed measures of recovery knowledge, attitudes, confidence/competence, as well as identifying significant learning events. Statistically significant improvements were found in terms of attitudes and confidence/competence, and only one recovery knowledge factor, ‘roles of self-definition and peers in recovery’. Recovery knowledge at the end of the internship was positively associated with increases in interns’ confidence/competence but was not associated with changes in the interns’ attitudes. The mentoring, training/feedback and observational elements of the internship programme were highly valued by interns. Competency based learning events were most frequently identified as significant. Strategies to increase self-directed and interpersonally focused learning, and specific personal recovery knowledge in training are discussed.

Ionic transport (for applications in nanofluidics or membranes) and "ionic diode" phenomena in a zeolitic imidazolate framework (ZIF-8) are investigated by directly growing the framework from aqueous Zn2+ and 2-methylimidazole as an "asymmetric plug" into a 20 μm diameter pore in a ca. 6 μm thin poly-ethylene-terephthalate (PET) film.

There is increasing emphasis on the use routine outcome assessment measures to inform quality assurance initiatives. The calculation of reliable and clinically significant change indices is one strategy that organizations could use to develop both internal and externally focused benchmarking processes. The current study aimed to develop reliable and clinically significant change indices for a range of commonly used outcome measures in the substance abuse field. Participants were attending Kedesh Rehabilitation Services, an Australian residential substance abuse service that also accepts people with co-occurring mental health problems (n = 595). A range of mental health and substance use measures were administered to participants at intake to the service, and just prior to discharge at 7-weeks. Participants demonstrated statistically significant improvement across each of the measures. Rates of clinically significant improvement varied from 44 % to 85 % dependent on the criteria and outcome measure used. The calculation of clinically significant change provides a low cost, and relatively straightforward approach to evaluating and benchmarking program activities. It is likely that the results from the current study will be beneficial for other residential substance abuse services looking to benchmark their own program activities.

In the sport of curling players sweep the ice in the front of curling stones to increase the distance that the projectiles slide. Their vigorous sweeping raises the surface temperature of the ice thereby reducing its coefficient of friction. The change in ice temperature is dependent on the velocity that curlers sweep the ice, the downward force they apply and the pattern that is swept. The forces and velocities applied by Olympic level curlers were recorded on an instrumented brush. A numerical model was used to determine optimal sweeping pattern based on the curlers sweep force and velocity profiles.

Rate constants have been measured in the gas phase and in liquid Ar solution at 85 K under 1 atm pressure for the irreversible deactivation of 13C16O(ν = 1), 13C16O(ν = 1) and 13C18O(ν = 1) by CD4 and by CD3H and of 12C16O(ν = 1) and 13C18O(ν = 1) by CF4. In every case of near-resonant energy transfer which we have examined we have found that the rate constants in the gas phase are greater than those in the liquid phase. We suggest that this is because long-range forces operate to a greater extent in the gas phase than in the liquid phase, resulting in a breakdown of the IBC hypothesis.

The increases in the populations of the vibrational levels v = 1 to v = 5 in CO which is undergoing thermal vibrational relaxation at 2100 K have been monitored using a cw CO laser. The experiments have been carried out in a very narrow temperature range for mixtures of CO, Ar and He. Under these conditions the first part of the relaxation region is clearly visible, and it has been possible to compare the population growths of different vibrational levels under the same conditions. We have shown that the curve for the increase in the population of the level v = 1 with time is clearly different from those of the higher levels. It has been shown that all of the vibrational levels studied in this work on CO relax with a common vibrational temperature, as postulated in the model of Shuler and co-workers. The results reported here are qualitatively different from those presented by Chow and Greene on HI.

Rate constants for non-resonant VV transfer from 12 CO( v = 1) to O 2 , CH 4 and N 2 ; from 13 CO( v = 1) to O 2 and N 2 ; and from N 2 ( v = 1) to CH 4 have been measured in liquid-argon solutions at 85 K. The results are compared with those obtained in the gas phase at the same temperature in this laboratory. In all cases the rate constants are the same in both phases within 10%. These results are at variance with the predictions of cell theory and cannot be accounted for adequately by the statistical theory of Delalande and Gale. Calculations are presented which show that collisions with remarkably low energies of ≈ 100 cm −1 (150 K) dominate the energy transfer processes at these low temperatures. However it is concluded that the isolated binary collision model is still applicable.

Rate constants for the vibrational deactivation of CD 4 by the collision partners CD 4 , He, Ne, Ar, Kr, D 2 and O 2 have been measured using a laser-fluorescence technique. The results are compared with those for the deactivation of CH 4 by the same collision partners and with a modified SSH type theoretical treatment.

Partitionable graphs have been studied by a number of authors in conjunction with attempts at proving the Berge Strong Perfect Graph Conjecture (SPGC). We give some new properties of partitionable graphs which can be used to give a new proof that the SPGC holds for K1,3-free graphs. Finally, we will show that the SPGC also holds for the class of circle graphs.

A graph G is called perfect if for every induced subgraph H of G , the minimum number of colors needed to color the vertices of H equals the size of the largest clique in H . In the early 1960s, Claude Berge conjectured that a graph G is perfect if and only if neither G nor its complement contain an odd length chordless cycle, and this has become known as the Strong Perfect Graph Conjecture (SPGC). A circle graph is one whose vertices can be put into one-to-one correspondence with the chords of a circle such that two vertices are adjacent if and only if their corresponding chords intersect. In this work we will prove that the SPGC is true for the class of circle graphs.