Fine and hyperfine excitation of CCN by He

2020 ◽  
Vol 497 (2) ◽  
pp. 1862-1869
Author(s):  
A Chefai ◽  
N E Jaidane ◽  
K Hammami ◽  
F Lique
Keyword(s):  
Rate Coefficients ◽  
Accurate Estimation ◽  
Circumstellar Envelopes ◽  
Hyperfine Transitions ◽  
Radiative Processes ◽  
Physical Conditions ◽  
Collisional Rate Coefficients ◽  
Coupled Channel ◽  
The Impact ◽  
First Time

ABSTRACT The relative abundance of cyanide and isocyanide molecules is a sensitive tracer of the physical conditions in the interstellar and circumstellar media. Accurate modelling of collisional and radiative processes implying these species opens the way for accurate estimation of their abundances. The present paper focuses on the computation of collisional rate coefficients for fine and hyperfine (de-)excitation of the CCN molecule (one of the C2N isomers) in collision with He, for temperatures up to 150 K. Using a time independent coupled-channel approach, scattering calculations were performed for transitions implying the lowest 56 fine structure levels and the corresponding 166 hyperfine structure levels belonging to both 2Π1/2 and 2Π3/2 spin-orbit manifolds. We provided, for the first time, realistic collisional data for the CCN radical. Propensity rules for fine and hyperfine transitions are discussed. As a first application, we evaluated the impact of these new data on the astrophysical modelling through radiative transfer calculations. We obtained the brightness and excitation temperatures of selected lines observed towards circumstellar envelopes and we found that local thermodynamic equilibrium conditions are not fulfilled for this species. As a consequence, our results indicate that the abundance of the CCN derived from the observations has to be revised since the observation modelling strongly depends on the collisional data used.

scholarly journals The excitation of OH by H2 revisited – II. Hyperfine resolved rate coefficients

2020 ◽  
Vol 493 (3) ◽  
pp. 3491-3495 ◽  
Author(s):  
J Kłos ◽  
P J Dagdigian ◽  
M H Alexander ◽  
A Faure ◽  
F Lique
Keyword(s):  
Molecular Clouds ◽  
Emission Spectra ◽  
Rate Coefficients ◽  
Star Forming ◽  
Physical Conditions ◽  
Star Forming Regions ◽  
Wide Range ◽  
State Rate ◽  
Collisional Rate Coefficients ◽  
Collisional Rate

ABSTRACT Observations of hyperfine resolved transitions of the hydroxyl radical (OH) are unique probes of the physical conditions in molecular clouds. In particular, hyperfine intensities can be used as an effective thermometer over a wide range of molecular densities. Accurate modelling of the OH emission spectra requires the calculation of collisional rate coefficients for the excitation of OH by H2, the most abundant collisional partner in the molecular clouds. Here, we determine hyperfine resolved rate coefficients for the excitation of OH by H2 using a recently developed highly accurate potential energy surface. State-to-state rate coefficients between the lower hyperfine levels were calculated using recoupling techniques for temperature ranging from 10 to 150 K. Significant differences were found with the earlier values currently used in astrophysical models, the new rate coefficients being larger than the previous ones. Finally, we compute the excitation of the OH radical in cold molecular clouds and star-forming regions. The new rate coefficients were found to increase the hyperfine intensities by a factor of ∼1–2. Consequently, we recommend using this new set of data in any astrophysical model of OH excitation.

scholarly journals The excitation of NH2 in the interstellar medium

2019 ◽  
Vol 490 (2) ◽  
pp. 2178-2182 ◽  
Author(s):  
N Bouhafs ◽  
A Bacmann ◽  
A Faure ◽  
F Lique
Keyword(s):  
Interstellar Medium ◽  
Energy Levels ◽  
Rate Coefficients ◽  
Accurate Estimation ◽  
Close Coupling ◽  
Star Forming ◽  
Star Forming Regions ◽  
Brightness Temperatures ◽  
Present Rate ◽  
Collisional Rate Coefficients

ABSTRACT Accurate estimation of the abundance of the NH2 radical in the interstellar medium requires accurate radiative and collisional rate coefficients. The calculation of hyperfine-resolved rate coefficients for the collisional (de-)excitation of NH2 by both ortho- and para-H2 is presented in this work. Hyperfine-resolved rate coefficients are calculated from pure rotational close-coupling rate coefficients using the Mj randomizing approximation. Rate coefficients for temperatures ranging from 5 to 150 K were computed for all hyperfine transitions among the first 15 rotational energy levels of both ortho- and para-NH2 in collisions with ortho- and para-H2. The new data were then employed in radiative transfer calculations to simulate the excitation of NH2 in typical star-forming regions such as W31C, where NH2 is seen in emission. We compared the excitation and brightness temperatures for different NH2 transitions obtained using the new and the previously available collisional data. It is found that the new rate coefficients increase the simulated line intensities by a factor ∼10–30. As a consequence, NH2 abundance derived from the observations will be significantly reduced by the use of the present rate coefficients.

scholarly journals Inelastic rate coefficients for collisions of N2H+ with H2

2020 ◽  
Vol 495 (2) ◽  
pp. 2524-2530 ◽  
Author(s):  
Christian Balança ◽  
Yohann Scribano ◽  
Jérôme Loreau ◽  
François Lique ◽  
Nicole Feautrier
Keyword(s):  
Channel Model ◽  
Molecular Ions ◽  
Rate Coefficients ◽  
Close Coupling ◽  
Excitation Rate ◽  
Hyperfine Transitions ◽  
Physical Conditions ◽  
Deep Well ◽  
State Rate ◽  
Highly Correlated

ABSTRACT N2H+ is one of the first molecular ions observed in the interstellar medium and it is of particular interest to probe the physical conditions of cold molecular clouds. Accurate modelling of the observed lines requires the knowledge of collisional excitation rate coefficients. Thus, we have calculated rate coefficients for the excitation of N2H+ by H2, the most abundant collisional partner. The calculations are based on a new potential energy surface obtained from highly correlated ab initio calculations. This 4D-interaction surface exhibits a very deep well of ≈2530 cm−1 making fully converged scattering calculations very difficult to carry out, when one takes into account the rotational structure of H2. To overcome this difficulty, two approximate approaches, the adiabatic hindered rotor approach (AHR) and the statistical adiabatic channel model, were tested by comparing the results with those obtained from full 4D close-coupling calculations. The AHR treatment, which reduces the scattering calculations to a 2D problem was found to give the best results at all temperatures and even for transitions involving high N2H+ rotational levels. State-to-state rate coefficients between the 26 first N2H+ rotational levels were calculated for temperatures ranging from 5 K up to 500 K. Using a recoupling technique, rate coefficients are obtained among hyperfine transitions.

scholarly journals Hyperfine excitation of SH+ by H

2020 ◽  
Vol 638 ◽  
pp. A72
Author(s):  
François Lique ◽  
Alexandre Zanchet ◽  
Niyazi Bulut ◽  
Javier R. Goicoechea ◽  
Octavio Roncero
Keyword(s):  
Accurate Determination ◽  
Rate Coefficients ◽  
High Mass ◽  
Hydrogen Atoms ◽  
Interstellar Clouds ◽  
Sulfur Chemistry ◽  
Hyperfine Transitions ◽  
Physical Conditions ◽  
Hydrogen Molecules ◽  
State Rate

Context. SH+ is a surprisingly widespread molecular ion in diffuse interstellar clouds. There, it plays an important role by triggering the sulfur chemistry. In addition, SH+ emission lines have been detected at the UV-illuminated edges of dense molecular clouds, so-called photo-dissociation regions (PDRs), and toward high-mass protostars. An accurate determination of the SH+ abundance and of the physical conditions prevailing in these energetic environments relies on knowing the rate coefficients of inelastic collisions between SH+ molecules and hydrogen atoms, hydrogen molecules, and electrons. Aims. We derive SH+–H fine and hyperfine-resolved rate coefficients from recent quantum calculations for the SH+–H collisions, including inelastic, exchange, and reactive processes. Methods. The method we used is based on the infinite-order sudden approach. Results. State-to-state rate coefficients between the first 31 fine levels and 61 hyperfine levels of SH+ were obtained for temperatures ranging from 10 to 1000 K. Fine-structure resolved rate coefficients present a strong propensity rule in favor of Δj = ΔN transitions. The Δj = ΔF propensity rule is observed for the hyperfine transitions. Conclusions. The new rate coefficients will help significantly in the interpretation of SH+ spectra from PDRs and UV-irradiated shocks where the abundance of hydrogen atoms with respect to hydrogen molecules can be significant.

The Smoulder Stream of Cigarettes / Zur Kenntnis des Glimmstromes von Cigaretten

1965 ◽  
Vol 3 (2) ◽  
Author(s):  
F. Seehofer ◽  
W. Schulz
Keyword(s):  
Moisture Content ◽  
Spatial Position ◽  
High Yield ◽  
Physical Conditions ◽  
Moisture Contents ◽  
Cigarette Paper ◽  
First Time

AbstractThe phenomenon of the smoulder stream flowing through the cigarette during smouldering and during the puff intervals is demonstrated for the first time and its dependence upon physical conditions is examined. The volume of the smoulder stream can amount up to 180 ml per cigarette. Increasing draw resistance of the cigarette and augmenting moisture content of the tobacco as well as perforation of the cigarette paper have a decreasing effect on volume and velocity of the smoulder stream. The porosity of the cigarette paper has no perceptible influence. The spatial position of the cigarette affects volume and velocity of the smoulder stream. The influence exercised by the smoulder stream on the yields of total condensate, nicotine, phenols, aldehydes, and acroleine when the cigarette tip is open during the puff intervals is determined. When the moisture contents of the tobacco were extremely high, yield decreases reaching 50 % could be observed.

Relationship between big five personality model and abusive supervision

2019 ◽  
Vol 12 (2) ◽  
Author(s):  
Bibi Tahira ◽  
Naveed Saif ◽  
Muhammad Haroon ◽  
Sadaqat Ali
Keyword(s):  
Big Five ◽  
Abusive Supervision ◽  
State Universities ◽  
Big Five Personality ◽  
Big Five Model ◽  
The Impact ◽  
First Time ◽  
Supervisor Behavior ◽  
Moderating Role

The current study tries to understand the diverse nature of relationship between personality Big Five Model (PBFM) and student's perception of abusive supervision in higher education institutions of Khyber Pakhtoonkhwa Pakistan. Data was collected in dyads i.e. (supervisors were asked to rate their personality attributes while student were asked to rate the supervisor behavior) through adopted construct. For this purpose, data was collected from three government state universities and one Private Sector University. The focus was on MS/M.Phill and PhD student and their supervisors of the mentioned universities. After measuring normality and validity regression analysis was conducted to assess the impact of supervisor personality characteristics that leads to abusive supervision. Findings indicate interestingly that except agreeableness other four attributes of (PBFM) are play their role for abusive supervision. The results are novel in the nature as for the first time Neuroticism, openness to experience, extraversion and conscientiousness are held responsible for the abusive supervision. The study did not explore the demographic characteristics, and moderating role of organizational culture, justice and interpersonal deviances to understand the strength of relationship in more detail way. Keywords: Personality big five model, abusive supervision, HEIs

The Influence of TRIPS Compliant Patent Laws on Indian Pharmaceutical Industry

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Rupesh Rastogi ◽  
Virendra Kumar
Keyword(s):  
Pharmaceutical Industry ◽  
Patent Protection ◽  
Uruguay Round ◽  
Pharmaceutical Products ◽  
Trips Agreement ◽  
Patent Law ◽  
Patent Laws ◽  
The Impact ◽  
First Time ◽  
Indian Pharmaceutical Industry

The first legislation in India relating to patents was the Act VI of 1856. The Indian Patents and Design Act, 1911 (Act II of 1911) replaced all the previous Acts. The Act brought patent administration under the management of Controller of Patents for the first time. After Independence, it was felt that the Indian Patents & Designs Act, 1911 was not fulfilling its objective. Various comities were constituted to recommend, framing a patent law which can fulfill the requirement of Indian Industry and people. The Indian Patent Act of 1970 was enacted to achieve the above objectives. The major provisions of the act, provided for process, not the product patents in food, medicines, chemicals with a term of 14 years and 5-7 for chemicals and drugs. The Act enabled Indian citizens to access cheapest medicines in the world and paved a way for exponential growth of Indian Pharmaceutical Industry. TRIPS agreement, which is one of the important results of the Uruguay Round, mandated strong patent protection, especially for pharmaceutical products, thereby allowing the patenting of NCEs, compounds and processes. India is thereby required to meet the minimum standards under the TRIPS Agreement in relation to patents and the pharmaceutical industry. India’s patent legislation must now include provisions for availability of patents for both pharmaceutical products and processes inventions. The present paper examines the impact of change in Indian Patent law on Pharmaceutical Industry.

The impact of traditional plants and their secondary metabolites in the discovery of COVID-19 treatment

2020 ◽  
Vol 26 ◽  
Author(s):  
Shabana Bibi ◽  
Ayesha Sarfraz ◽  
Ghazala Mustafa ◽  
Zeeshan Ahmed ◽  
Muhammad Aurang Zeb ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Test System ◽  
Chemical Information ◽  
System Type ◽  
The Family ◽  
Comprehensive Search ◽  
Coronavirus Infection ◽  
The Impact ◽  
First Time ◽  
Plant Sources

Background: Coronavirus Disease-2019 belongs to the family of viruses which cause a serious pneumonia along with fever, breathing issues and infection of lungs for the first time in China and later spread worldwide. Objective: Several studies and clinical trials have been conducted to identify potential drugs and vaccines for Coronavirus Disease-2019. The present study listed natural secondary metabolites identified from plant sources with antiviral properties and could be safer and tolerable treatment for Coronavirus Disease-2019. Methods: A comprehensive search on the reported studies was conducted using different search engine such as Google scholar, SciFinder, Sciencedirect, Medline PubMed, and Scopus for the collection of research articles based on plantderived secondary metabolites, herbal extracts, and traditional medicine for coronavirus infections. Results: Status of COVID-19 worldwide and information of important molecular targets involved in COVID-19 is described and through literature search, is highlighted that numerous plant species and their extracts possess antiviral properties and studied with respect to Coronavirus treatments. Chemical information, plant source, test system type with mechanism of action for each secondary metabolite is also mentioned in this review paper. Conclusion: The present review has listed plants that have presented antiviral potential in the previous coronavirus pandemics and their secondary metabolites which could be significant for the development of novel and a safer drug which could prevent and cure coronavirus infection worldwide.

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