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Introduction Working at Covid-19 frontline may threaten physical and mental health healthcare workers (HCWs). Assessing perceived Stress in HCWs is important to prevent serious mental illness Objectives Assess the association between perceived stress and risk perception among healthcare workers working in the Covid-19 unit. Methods We conducted a cross-sectional study among healthcare workers working in a COVID-19 unit between March and July 2021 through a self-administered questionnaire. The Perceived Stress Scale (PSS-10) was used to assess perceived stress. The perceived risk of getting infected was assessed by a 5-item Likert Scale. The perceived risk of family members’ infection was evaluated by a Scale from 0 to 10. Results A total of 85 participants were included. The mean age was 31±6 years. About 87% of participants lived with their families. Seventy-six per cent of HCWs rated their health status greater than or equal to 8/10. A percentage of 18,8% of HCWs have been infected with the Covid-19. Our population consisted of 44.7% technicians and 24,7% nurses, and 80% of the participants reported direct contact with COVID-19 confirmed patients. The level of the perceived risk of getting infected was high to very high in 95% of the HCWs. The mean score of the perceived risk of family members contracting the virus was 5.7 and 27,1% rated it greater than or equal to 8. The PSS-10 showed moderate and high perceived stress in 82,3% and 7,1% of participants, respectively. Only 10,6% of HCWs presented low-stress perception. Conclusions Frontline healthcare providers have high perceived stress and are at risk of mental health disorders Disclosure No significant relationships.

Introduction Covid-19 vaccination in adults become a common behaviour nowadays. It may induce stress in some of the vaccinated patients. Objectives This study aimed to evaluate perceived Stress among university teachers desiring to be vaccinated. Methods We conducted a cross-sectional study on Tunisian university teachers who participated in a COVID-19 vaccination campaign organized in June 2021. A self-administered questionnaire was administered. The survey dealt with socio-professional data and the level of stress assessed with the Perceived Stress Scale (PSS-10). Results A total of 100 participants were included. The mean age was 51 years ±7. The Sex Ratio (M/F) was 1.7. The majority of participants were married and reported living with their families (96%). On a 0 to 10 scale, 71% of participants described an excellent health status and rated it greater than or equal to 8. The average job tenure was 15 years. The PSS-10 showed moderate and high perceived stress in 86% and 4% of participants, respectively. Only 10% of university teachers presented low-stress perception. Conclusions Getting vaccinated against Covid-19 is crucial in order to protect the population. This behaviour could be associated with a big amount of stress. Taking into account the psychiatric mental condition is crucial for the vaccinating health care providers in order to alleviate this experience. Disclosure No significant relationships.

Introduction Over the past decades, a growing body of evidence has demonstrated the impact of the psychosocial work environment on workers’ health, safety and wellbeing. These factors may also affect employees ’job satisfaction. Objectives To explore psychosocial determinants of job satisfaction among workers in a Tunisian electricity and gas company. Methods A cross-sectional survey was conducted among male workers in a Tunisian electricity and gas company. The Copenhagen Psychosocial Questionnaire (COPSOQ), the Job Content Questionnaire and the general health questionnaire (GHQ12) were used to assess psychosocial risk factors at work. A principal component analysis (PCA) was used to assess correlations between instruments ’scores. Multiple linear regression analysis was applied to explore the specific factors associated with job satisfaction. Data were analysed using R software. Results A total of 83 workers participated in the survey (the age range: 21-60 years). Job satisfaction score varied from 0 to 100% with a mean of 73.09 %. In the PCA, job satisfaction had a positive correlation with high social support and a negative one with work-family conflicts, a high psychological demand, stress, burnout and quantitative demands. In multivariate analysis, factors negatively associated with job satisfaction were: age, stress and low social support. In contrast, seniority was positively associated with job satisfaction. Conclusions Job satisfaction is deeply influenced by the psychosocial work environment. Therefore, it is necessary to provide supervision, communication, and social support for these workers to increase or maintain a high level of job satisfaction. Disclosure No significant relationships.

Introduction Nursing is highly demanding and stressful profession. Therefore, maintaining and improving psychological wellbeing among nurses seems essential to have a better life satisfaction and a better productivity. Objectives The aim of this study was to assess the relationship between mental health and life satisfaction among nurses. Methods The study was conducted in a group of active nurses from Hedi Chaker hospital in Sfax- Tunisia. Standardized questionnaires were used, including the general health questionnaire (GHQ-28) and the satisfaction with life scale (SWLS). Results A total of 100 (males = 40; females = 60) nurses participated in this study. The mean age was 50.20 ±7.20 years. The average of job tenure was 25.25 ± 9.70 years. The majority of participants (66.7%) reported having chronic diseases. Rotating shifts work was noted in 72.50% of cases. Average scores for the GHQ-28 and the SWLS were respectively 30.66 ± 11.07 and 21.61± 6.23. The presence of chronic conditions was associated with psychological distress (higher GHQ-28 scores) (p = 0.01). Life satisfaction score was positively correlated with age (r= 0.29, p= 0.023), whereas it was negatively correlated with GHQ-28 scores (r= -0.36, p= 0.01). Low life satisfaction (SWLS scores between 5 and 14) was significantly associated with three domains of the GHQ-28: somatic symptoms (p = 0.008), anxiety (p = 0.001) and social dysfunction (p = 0.01). Conclusions According to our study, low life satisfaction was associated with psychological disorder. Hence, nurses need support and subsequent interventions in order to improve psychological wellbeing and life-satisfaction. Disclosure No significant relationships.

Introduction A growing body of literature has documented that occupational stress is associated with increased risks of musculoskeletal injuries or symptoms. Objectives The purpose of this study was to assess the effect of occupational stress on the occurrence of musculoskeletal symptoms among workers in a Tunisian footwear industry. Methods Material and methods: This was an exhaustive and cross-sectional study including workers in a footwear industry. Musculoskeletal symptoms were assessed using a modified Nordic questionnaire. We used the Job Demand/Control model of Karasek to measure occupational stress. The Quick Exposure Check (QEC) method was used as an ergonomic risk assessment tool. Data were analysed using R software. Results A total of 337 workers participated in the survey (the age range: 18-60 years). A total of 83.7 of workers reported musculoskeletal symptoms at one site or more. Elbows and upper back were the most symptomatic sites in respectively 84% and 65%. We noted job-strain and iso-strain situations in respectively 57% and 32%. In 78.1% of the workers studied, the QEC score was high and very high in 21.9%. Multivariable-adjusted logistic regression model showed that iso-strain situation was associated with the number of symptomatic sites (p= 0.0003, OR=1.34), having musculoskeletal symptoms in elbows (p= 0.03, OR=2.33) and upper back (p=0.009, OR=2.40), and the final QEC score (p= 0.018, OR= 1.04). Conclusions Occupational stress constitutes a significant risk for this leather industry. It is associated with a higher prevalence of musculoskeletal symptoms in the workplace and with work-related biomechanical exposure. Disclosure No significant relationships.

Introduction Being a victim of work-related upper extremity injuries is a source of physical damage and mental damages. Psychological distress related to this type of accident is usually underestimated. Objectives Evaluate anxiety and depression among victims of work-related upper extremity injuries. Methods We conducted a 10-month cross-sectional analysis on workers consulting for an Impairment Rating Evaluation after an upper extremity injury due to an occupational accident. We collected socio-professional data, characteristics and outcomes of the accident. Anxiety and depression were evaluated by the Hospital Anxiety and Depression scale. The pain was evaluated by a Visual Analogue Scale. Results Our population consisted of 90 cases of work-related upper-extremity injuries. The mean age was 43.10 and the sex ratio 3.7. The most represented category was blue-collar workers (71.1%). Medical history of chronic diseases was reported in 23% of cases and 3.3 % had mental health antecedent. Dominant upper limb injuries were found in 62% of cases. Hand and wrist injuries were the most affected part (63%), and 33.3% had fingers’ injuries. The prevalence of anxiety and depression were 31.1% and 20% respectively. About thirty-one per cent rated their current pain greater than or equal to 8. Both anxiety and depression were positively correlated with male gender (p= 0.001, p=0.007) and shoulder injuries (p=0.001, p=0.018). Depression was correlated to fingers’ injuries and pain (p=0.002). Conclusions The studied population present an important rate of anxiety and depression. Assessing Mental health after upper extremities injuries are necessary to prevent serious mental illness and to promote a successful return to work. Disclosure No significant relationships.

Introduction Post-traumatic stress disorder frequently alters the quality of life. Objectives Assess the quality of life in midwives who have post-traumatic stress disorder. Methods We conducted a cross-sectional study among midwives in a single university hospital centre using a self-administered questionnaire. We screened post-traumatic stress disorder using the Impact of event scale and the quality of life using 5 items Likert scale. Results Our response rate was 82%. Out of 42 midwives who answered us, 18 had post-traumatic stress disorder symptoms (42.8%). They were all female. Their mean age was 45.6± 10.3 years. The traumatic event occurred mainly at work and was related to the death of a mother or a baby. Symptoms of post-traumatic stress disorder symptoms were severe in 5 midwives. The quality of life was altered in 38.8% of participants. Both post-traumatic stress disorder symptoms and alteration of the quality of life were more frequent in patients who don’t have leisure activities. Conclusions In conclusion, midwives are vulnerable to developing post-traumatic stress disorder. Encouraging sports and other leisure activities may protect them from having severe repercussions on their life. Disclosure No significant relationships.

The present study examines the use of waste cooking oil (WCO) as a substrate for medium-chain-length polyhydroxyalkanoates (mcl-PHA) production by Pseudomonas rhizophila S211. The genome analysis revealed that the S211 strain has a mcl-PHA cluster ( phaC1ZC2DFI ) encoding two class II PHA synthases (PhaC1 and PhaC2) separated by a PHA depolymerase (PhaZ), a transcriptional activator (PhaD) and two phasin-like proteins (PhaFI). Genomic annotation also identified a gene encoding family I.3 lipase that was able to hydrolyze plant oils and generate fatty acids as favorable carbon sources for cell growth and PHA synthesis via β-oxidation pathway. Using a three-variable Doehlert experimental design, the optimum conditions for mcl-PHA accumulation were achieved in 10% of WCO-based medium with an inoculum size of 10% and an incubation period of 48 h at 30 °C. The experimental yield of PHA from WCO was 1.8 g/L close to the predicted yield of 1.68 ± 0.14 g/L. Moreover, 1 H nuclear magnetic resonance spectroscopy analysis confirmed the extracted mcl-PHA. Overall, this study describes P. rhizophila as a cell factory for biosynthesis of biodegradable plastics and proposes green and efficient approach to cooking oil waste management by decreasing the cost of mcl-PHA production, which can help reduce the dependence on petroleum-based plastics., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest in the publication., (© King Abdulaziz City for Science and Technology 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

Considering the current growing interest in new and improved enzymes for use in a variety of applications, the present study aimed to characterize a novel detergent-stable serine alkaline protease from the extremophilic actinobacterium Microbacterium metallidurans TL13 (MmSP) using a combined in silico and experimental approach. The MmSP showed a close phylogenetic relationship with high molecular weight S8 peptidases of Microbacterium species. Moreover, its physical and chemical parameters computed using Expasy's ProtParam tool revealed that MmSP is hydrophilic, halophilic and thermo-alkali stable. 3D structure modelling and functional prediction of TL13 serine protease resulted in the detection of five characteristic domains: [catalytic subtilase domain, fibronectin (Fn) type-III domain, peptidase inhibitor I9, protease-associated (PA) domain and bacterial Ig-like domain (group 3)], as well as the three amino acid residues [aspartate (D182), histidine (H272) and serine (S604)] in the catalytic subtilase domain. The extremophilic strain TL13 was tested for protease production using agricultural wastes/by-products as carbon substrates. Maximum enzyme activity (390 U/gds) was obtained at 8th day fermentation on potato peel medium. Extracellular extract was concentrated and partially purified using ammonium sulfate precipitation methodology (1.58 folds purification fold). The optimal pH, temperature and salinity of MmSP were 9, 60 °C and 1 M NaCl, respectively. The MmSP protease showed broad pH stability, thermal stability, salt tolerance and detergent compatibility. In order to achieve the maximum stain removal efficacy by the TL 13 serine protease, the operation conditions were optimized using a Box-Behnken Design (BBD) with four variables, namely, time (15-75 min), temperature (30-60 °C), MmSP enzyme concentration (5-10 U/mL) and pH (7-11). The maximum stain removal yield (95 ± 4%) obtained under the optimal enzymatic operation conditions (treatment with 7.5 U/mL of MmSP during 30 min at 32 °C and pH9) was in good agreement with the value predicted by the regression model (98 ± %), which prove the validity of the fitted model. In conclusion, MmSP appears to be a good candidate for industrial applications, particularly in laundry detergent formulations, due to its high hydrophilicity, alkali-halo-stability, detergent compatibility and stain removal efficiency., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest in the publication., (© King Abdulaziz City for Science and Technology 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

The theoretical study of collisions between atoms and molecules provides a detailed description of the involved mechanisms and greatly contributes to improving atmospheric and astrophysics models. In the present paper, we focus on the new calculation of rate coefficients for the first 25 rotational levels of the CaNC molecule in collision with He. A new 2D potential energy surface (2D-PES), for the CaNC-He system, was determined using the single, double and perturbative triple excitation restricted coupled-cluster method [rccsd(t)] and the standard aug-cc-pVQZ basis sets. This PES presents a global minimum with a well depth of -21.93 cm -1 located at R = 8 a 0 and γ = 116°. State-to-state collisional excitation cross-sections of the fine-structure levels of CaNC( 2 Σ + , which yield, after thermal averaging, rate coefficients up to 70 K. A Δ -1 , which yield, after thermal averaging, rate coefficients up to 70 K. A Δ J = Δ N propensity rule was observed. A comparison of the CaNC rates with those of valence isoelectronic MgNC has been investigated. These new data are necessary for the CaNC abundance determination and interpretation of its observed lines.

Microbial polyhydroxyalkanoates (PHA) are biodegradable and biocompatible bio-based polyesters, which are used in various applications including packaging, medical and coating materials. In this study, an extremophilic hydrocarbonoclastic bacterium, previously isolated from saline sediment in the Tunisian desert, has been investigated for PHA production. The accumulation of intracellular PHA granules in Halomonas desertis G11 was detected by Nile blue A staining of the colonies. To achieve maximum PHA yield by the strain G11, the culture conditions were optimized through response surface methodology (RSM) employing a Box-Behnken Design (BBD) with three independent variables, namely, substrate concentration (1-5%), inoculum size (1-5%) and incubation time (5-15 days). Under optimized conditions, G11 strain produced 1.5 g/L (68% of DCW) of PHA using glycerol as a substrate. Application of NMR (1H and 13C) and FTIR spectroscopies showed that H. desertis accumulated PHA is a poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV). The genome analysis revealed the presence of typical structural genes involved in PHBV metabolism including phaA , phaB , phaC , phaP , phaZ , and phaR , coding for acetyl-CoA acetyltransferase, acetoacetyl-CoA reductase, class I polyhydroxyalkanoates synthases, phasin, polyhydroxyalkanoates depolymerase and polyhydroxyalkanoates synthesis repressor, respectively. Glycerol can be metabolized to 1) acetyl-CoA through the glycolysis pathway and subsequently converted to the 3HB monomer, and 2) to propionyl-CoA via the threonine biosynthetic pathway and subsequently converted to the 3HV monomer. In silico analysis of PhaC1 from H. desertis G11 indicated that this enzyme belongs to Class I PHA synthase family with a "lipase box"-like sequence (SYCVG). All these characteristics make the extremophilic bacterium H. desertis G11 a promising cell factory for the conversion of bio-renewable glycerol to high-value PHBV., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Hammami, Souissi, Souii, Ouertani, El-Hidri, Jabberi, Chouchane, Mosbah, Masmoudi, Cherif and Neifar.)

An appropriate estimation of the abundance of the observed C 5 radical in the interstellar medium requires accurate radiative and collisional rate coefficients. We present the first two-dimensional potential energy surface (2D-PES) for the ground electronic state of the C 5 (X 1 Σ + )-He(X 1 S) van der Waals system, obtained using an explicitly correlated coupled-cluster method with single, double, and perturbative triple excitations (RCCSD(T)-F12). This PES is subsequently used in quantum close-coupling (CC) scattering calculations. Collisional excitation cross-sections of the rotational levels of C 5 by He were calculated for energies up to 1500 cm -1 using the standard (CC) method. The thermal dependence of the corresponding rate coefficients is given for the low and moderate temperature T ≤ 300 K regime of interstellar molecular clouds. This is the first study on the collisional rate coefficients for this system and may have important implications for the astrophysical detection of C 5 (X 1 Σ + ) and modeling of carbon-rich media.

Among all the molecular species found in the interstellar medium, molecules with threefold symmetry axes play a special role, as their rotational spectroscopy allows them to act as practical gas thermometers. Methyl-cyanide (CH3CN) is the second most abundant of those (after ammonia). We compute in this paper the collisional dynamics of methyl-cyanide in collision with helium, for both the A- and the E-symmetries of CH3CN. The potential energy surface is determined using the CCSD(T)-F12b formalism and fit with convenient analytic functions. We compute the rotationally inelastic cross sections for all levels up to 510 cm-1 of collision energy, employing at low energy exact Coupled Channels methods, and at higher energies, approximate Coupled States methods. For temperatures from 7 K up to 300 K, rates of quenching are computed and most are found to differ from those reported earlier (up to a factor of a thousand), calling for a possible reexamination of the temperatures assigned to low density gasses.

Methane is an ubiquitous molecule, present as a minor component in many environments, including the Earth and planet atmospheres. Its van der Waals interaction with the main gases is an important ingredient for the understanding of radiative properties for those atmospheres. We present here the first precise determination of the interaction between CH 4 and H 2 . We compute the interaction in an ab initio coupled cluster formalism, with extended atomic bases. We compare a pure CCSD(T) approach to an explicitly correlated CCSD(T)-F12a formalism. The full geometry of scattering two rigid molecules is used, resulting in a potential energy surface depending on 5 degrees of freedom. The long-range part of the ab initio computation is compared with an analytic multipolar expansion. The potential is fit onto a suitable formalism for subsequent scattering dynamics. The potential well is computed at -92.92 cm -1 , an intermediate value if compared with other methane-diatomic molecule interactions.

Alkali aluminum hydroxide, AlOH, has associated features with the chemistry of aluminum-bearing species and generally with metal hydroxide molecules in the interstellar clouds where it has been observed. The aim of this work is to obtain accurate rotational rate coefficients of AlOH colliding with the most abundant molecular species in the interstellar medium (ISM), H2, in its lowest rotational state p-H2(J = 0) for the kinetic temperature range 5-80 K. A full and accurate 4D-PES was generated using explicitly correlated coupled cluster with single, double and perturbative triple excitation CCSD(T)-F12a augmented by the aVTZ basis set. Both the close coupling CC and coupled states CS techniques were used to generate rotational cross-sections for AlOH-p-H2 including 13 rotational states (J1 = 0,…,12) for the AlOH molecule and the J2 = 0 state for the H2 molecule for energy thresholds up to E = 500 cm-1. Propensity rules that favor odd ΔJ1 transitions are found all over the temperature range. Further, a comparison of the present AlOH-p-H2(J = 0) rate coefficients with scaled AlOH-He rates was made, revealing mainly good agreement with some discrepancies appearing for large ΔJ1. The use of the present rates is viewed to be a good tool to estimate the aluminum hydroxide abundance.

Cyclopropenylidene, c-C3H2, is a simple hydrocarbon, ubiquitous in astrophysical gases, and possessing a permanent electric dipole moment. Its readily observed rotational transitions make it an excellent probe for the physics and history of interstellar matter. The collisional properties of c-C3H2 with the main background gas, H2, are computed here. We present a full 5-D Potential Energy Surface in the rigid molecule approach, and fit it to relevant functionals for subsequent scattering. We perform low-energy quantum scattering at energies less than 50 cm-1. We use both ortho and para H2 as projectiles. We determine the quality of the various approximations to exact coupled channel scattering and examine paths to go towards higher energy scattering relevant for astrophysics. We compare the results obtained here with earlier ones for scattering with helium.

Tricarbon monoxide (C3O) is an astrochemically important molecule. It is a probe element for determining the chemical composition of gases in molecular clouds, as C3O is a major intermediate of ion-molecule reactions in the gas phase. For C3O, no collision coefficients are available in the literature. To estimate the abundance of C3O in a solar cold dark cloud: Taurus Molecular Cloud 1 (TMC-1) and find the range of cloud parameters, some authors used the calculated values for the HC3N molecule, which is isoelectronic and has similar rotational constants. Indeed, the calculation of the rate coefficients of C3O(1Σ+) induced by collision with He is performed for thermal temperatures below 25 K. These calculations are based on a new two-dimensional potential energy surface obtained from the explicitly correlated coupled cluster with a single, double and perturbative triple excitation (ccsd(t)-f12) ab initio approach associated with aug-cc-pVTZ basis sets. The PES was found to have a global minimum at (R = 6.2 Bohr and θ = 73°) with a depth of -53.4 cm-1 below the C3O-He dissociation limit. Using this PES, the integral cross sections are performed in the close-coupling quantum time independant formalism for Ec ≤ 110 cm-1 and J ≤ 12. These cross sections were then averaged at low temperature to obtain the downward rate coefficients. The new collisional data should significantly help the interpretation of interstellar C3O emission lines observed with current and future telescopes. We expect that they will allow the accurate determination of the C3O abundance in the interstellar medium, which is crucial to understand the chemistry of carbon chain species in the interstellar gas.

Among the closed-shell hydrocarbons, the carbenes c- and l-C 3 H 2 are the lightest ones to display a permanent electric dipole moment and be detectable by rotational spectroscopy. The cyclic form, cyclopropenylidene, is ubiquitous in the InterStellar Matter (ISM) of the Milky Way and external galaxies. As such, it serves as a marker to help in characterizing the physical conditions of the ISM. The linear form, propadienylidene, is less abundant. In order to get access to their absolute and relative abundances, it is essential to understand their collisional excitation/quenching schemes. We compute here a precise ab initio potential energy surface for the interaction of c- and l-C 3 H 2 with helium, by means of a CCSD(T)-F12a formalism and a fit onto relevant spherical harmonics functions. We conduct quantum dynamical scattering in order to get precise cross sections using a coupled-channel approach for solving the nuclear motion. We average sections to have rates for rotational quenching from 5 to 150 K. We show that these new rates are vastly different, up to more than an order of magnitude, from the older rates presented in the literature, computed with angular momentum algebra only. We expect large differences in the astrophysical analyses of C 3 H 2 , including the chemical history of those ubiquitous carbenes.

The CCN radical has been recently detected in the interstellar medium. Accurate modeling of its abundance in such media requires one to model its excitation by both radiation and collisions. Here, we report the first quantum mechanical close-coupling study of CCN-He collisions. Calculations of fine-structure resolved excitation cross sections of CCN(X 2 Π) induced by collision with He are performed for kinetic energies below 500 cm -1 . The calculations are based on new two-dimensional potential energy surfaces obtained from coupled cluster approaches. We found that the inelastic cross sections for spin-orbit conserving transitions are larger than those for spin-orbit changing transitions. The new collisional data should significantly help the interpretation of interstellar CCN emission lines observed with current and future telescopes and we expect that they will allow accurate determination of the CCN abundance in the interstellar medium, which is crucial to understand the chemistry of carbon chain species in the interstellar gas.

Isocyanic acid (HNCO) is the most stable of all its isomers; it has been observed repeatedly in many different conditions of the Interstellar Media, and its chemistry is poorly known. To quantitatively estimate the abundance of HNCO with respect to other organic molecules, we compute its rotational quenching rates colliding with H 2 , the most common gas in the gaseous Interstellar Media. We compute ab initio the van der Waals interaction HNCO-H 2 , in the rigid molecules approximation, with a CCSD(T)-F12a method. On the fitted ab initio surface, inelastic scattering cross sections and rates are calculated for a temperature range of 7-200 K, with the coupled-states quantum time-independent formalism. The critical densities are high enough to yield rotational temperatures of HNCO differing significantly from the kinetic temperature of H 2 , especially so for the shorter wavelengths observed at the ALMA interferometer. It is found that the quenching rates for collisions with ortho- or para-H 2 differ greatly, opening the possibility of far from equilibrium populations of some rotational levels of HNCO.

Phosphorus bearing molecules have been discovered in the circumstellar and interstellar media. Modeling their abundance accurately requires computations of rate coefficients induced by collision with He and H 2 (i.e., the most abundant gaseous components). These calculations may be carried out by first determining highly accurate potential energy surface (PES) and cross sections. In this paper, we present the first PES of the CP(X 2 Σ + )-He( 1 S) van der Waals collisional complex. The ab initio interaction potential was performed using the explicitly correlated restricted coupled cluster approach with simple, double, and perturbative triple excitation (RCCSD(T)-F12) in connection with the augmented-correlation consistent-polarized valence triple-ζ Gaussian basis set (aug-cc-pVTZ). The potential presents two minima of -18.62 cm -1 and -18.72 cm -1 . From the PES obtained, we have computed state-to-state excitation cross sections of CP due to collision with He for energies up to 500 cm -1 . Rotational transitions involving the fine-structure levels of the CP molecule were treated with a recoupling technique based on the scattering matrix calculated with the exact quantum mechanical close coupling method. Discussions on the propensity rules between the fine-structure levels were made and we found that the Δj = ΔN transitions are favored with respect to the Δj ≠ ΔN ones. The data presented in this paper may have a great impact on the accurate determination of the CP abundance in space.

Collisional energy transfer under cold conditions is of great importance from the fundamental and applicative point of view. Here, we investigate low temperature collisions of the SH - anion with He. We have generated a three-dimensional potential energy surface (PES) for the SH - (X 1 Σ + )-He( 1 S) van der Waals complex. The ab initio multi-dimensional interaction PES was computed using the explicitly correlated coupled cluster approach with simple, double, and perturbative triple excitation in conjunction with the augmented-correlation consistent-polarized valence triple zeta Gaussian basis set. The PES presents two minima located at linear geometries. Then, the PES was averaged over the ground vibrational wave function of the SH - molecule and the resulting two-dimensional PES was incorporated into exact quantum mechanical close coupling calculations to study the collisional excitation of SH - by He. We have computed inelastic cross sections among the 11 first rotational levels of SH - for energies up to 2500 cm -1 . (De-)excitation rate coefficients were deduced for temperatures ranging from 1 to 300 K by thermally averaging the cross sections. We also performed calculations using the new PES for a fixed internuclear SH - distance. Both sets of results were found to be in reasonable agreement despite differences existing at low temperatures confirming that accurate predictions require the consideration of all internal degrees of freedom in the case of molecular hydrides. The rate coefficients presented here may be useful in interpreting future experimental work on the SH - negative ion colliding with He as those recently done for the OH - -He collisional system as well as for possible astrophysical applications in case SH - would be detected in the interstellar medium.

A theoretical study of rotational collision of LiH(X(1)Σ(+),v = 0, J) with Ar has been carried out. The ab initio potential energy surface (PES) describing the interaction between the Ar atom and the rotating LiH molecule has been calculated very accurately and already discussed in our previous work [Computational and Theoretical Chemistry 993 (2012) 20-25]. This PES is employed to evaluate the de-excitation cross sections. The ab initio PES for the LiH(X(1)Σ(+))-Ar((1)S) Van der waals system is calculated at the coupled-cluster [CCSD(T)] approximation for a LiH length fixed to an experimental value of 3.0139 bohrs. The basis set superposition error (BSSE) is corrected and the bond functions are placed at mid-distance between the center of mass of LiH and the Ar atom. The cross sections are then derived in the close coupling (CC) approach and rate coefficients are inferred by averaging these cross sections over a Maxwell-Boltzmann distribution of kinetic energies. The 11 first rotational levels of rate coefficients are evaluated for temperatures ranging from 10 to 300 K. We notice that the de-excitation rate coefficients appear large in the order 10(-10) cm(-3) s(-1) and show very low temperature dependence. The rate coefficients magnify significantly the propensity toward ∆ J = -1 transitions. These results confirm the same propensity already noted for the cross sections.

We closely compare the accuracy of multidimensional potential energy surfaces (PESs) generated by the recently developed explicitly correlated coupled cluster (CCSD(T)-F12) methods in connection with the cc-pVXZ-F12 (X = D, T) and aug-cc-pVTZ basis sets and those deduced using the well-established orbital-based coupled cluster techniques employing correlation consistent atomic basis sets (aug-cc-pVXZ, X = T, Q, 5) and extrapolated to the complete basis set (CBS) limit. This work is performed on the benchmark rare gas-hydrogen halide interaction (HCl-He) system. These PESs are then incorporated into quantum close-coupling scattering dynamical calculations in order to check the impact of the accuracy of the PES on the scattering calculations. For this system, we deduced inelastic collisional data including (de-)excitation collisional and pressure broadening cross sections. Our work shows that the CCSD(T)-F12/aug-cc-pVTZ PES describes correctly the repulsive wall, the van der Waals minimum and long range internuclear distances whereas cc-pVXZ-F12 (X = D,T) basis sets are not diffuse enough for that purposes. Interestingly, the collision cross sections deduced from the CCSD(T)-F12/aug-cc-pVTZ PES are in excellent agreement with those obtained with CCSD(T)/CBS methodology. The position of the resonances and the general shape of these cross sections almost coincide. Since the cost of the electronic structure computations is reduced by several orders of magnitude when using CCSD(T)-F12/aug-cc-pVTZ compared to CCSD(T)/CBS methodology, this approach can be recommended as an alternative for generation of PESs of molecular clusters and for the interpretation of accurate scattering experiments as well as for a wide production of collisional data to be included in astrophysical and atmospherical models.

The interaction potential energy surface of the methinoposphide (HCP)-H(2) complex is calculated at the ab initio coupled-cluster level of theory with an aug-cc-pVTZ Gaussian basis set. The [H-C] and [C-P] bond lengths of HCP are set to their values at the linear equilibrium ground vibrational level of the molecule. The calculated interaction energy presents two minima located 106.3 and 67.6 cm(-1) below the HCP+H(2) dissociation limit. Using the interaction potential obtained, we have computed collision excitation cross sections in the close-coupling approach and downward rate coefficients at low temperature, i.e., T

A three-dimensional potential energy surface has been calculated for the ground electronic state of the HOCO+-He system. The calculations were performed at the coupled electron pair approximation level with an extended basis set which ensures a balance between accuracy and feasability. The validity of the method and of the basis set was tested through calculations of the polarizability of the He atom and of the spectroscopic constants of the HOCO+ ion. The calculated potential energy surface has been fitted to a spherical harmonic expansion to facilitate calculations of rotational excitation of HOCO+ by collisions with He.