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The kinetics and energetic relaxation associated with collisions between fast and thermal atoms are of fundamental interest for escape and therefore also for the evolution of the Mars atmosphere. The total and differential cross-sections of fast O($^3P$) atom collisions with CO have been calculated from quantum mechanical calculations. The cross-sections are computed at collision energies from 0.4 to 5 eV in the center-of-mass frame relevant to the planetary science and astrophysics. All the three potential energy surfaces ($^3$A', $^3$A" and 2 $^3$A" symmetry) of O($^3P$) + CO collisions separating to the atomic ground state have been included in calculations of cross-sections. The cross-sections are computed for all three isotopes of energetic O($^3P$) atoms collisions with CO. The isotope dependence of the cross-sections are compared. Our newly calculated data on the energy relaxation of O atoms and their isotopes with CO molecules will be very useful to improve the modeling of escape and energy transfer processes in the Mars' upper atmosphere., Comment: 8 pages, 6 figures

Mars has changed from a warmer, water-containing planet into a cold and arid environment. Collisions of superthermal oxygen and other atoms with surrounding gases may lead to the escape of light atmospheric molecules, such as D1, OH2, He3, and H24, from the Martian atmosphere. Such processes have probably contributed to the thinning of its atmosphere and the transformation of Mars' climate. OH molecules can be produced in the Martian atmosphere by the photodissociation of water vapor and in several chemical reactions, such as the reactions of thermal molecular hydrogen and energetic oxygen atoms O + H2 → H + OH 5. Emission and absorption spectra of OH molecules within the Martian atmosphere can lead to a better understanding of these processes. For example, they can help monitor the variation of its abundance with altitude 6. In general, astronomical spectra of specific molecules can be better interpreted through a detailed identification of their line list. In this work, we present an extensive line list for the B2S+ - X2P and D2S- - X2P electronic transitions of OH, including line intensities, line positions with the relevant quantum numbers of the upper and lower states, e/f parity and oscillator strength, calculated using PGOPHER7 program. The line intensities are found based on calculated ab-initio Transition Dipole Moment Function and potential energy curves obtained using the quantum computational chemistry program MOLPRO8, using CASSCF method followed by MRCI including Davidson correction term (+Q). LEVEL9 program is used to compute Transition Dipole Moment Matrix Elements in Hund's case (b) using the procedure of Numerov-Cooley10 which are then transformed to Hund's case (a) as required by PGOPHER. 1 P. Zhang, V. Kharchenko, M. Jamieson, and A. Dalgarno, "Energy Relaxation in Collisions of Hydrogen and Deuterium with Oxygen Atoms," J. Geophys. Res. 114, A07101 (2009). 2 M. Gacesa, N. Lewkow, and V. Kharchenko, "Non-thermal escape of molecular hydrogen from Mars," Icarus, L10203 (2012). 3 S. Bovino et al., "Energy Transfer in O Collisions with He Isotopes and Helium Escape from Mars," Geophys. Res. Lett., 38, L02203 (2011). 4 M. Gacesa, P. Zhang, and V. Kharchenko, "Non-thermal escape of molecular hydrogen from Mars," Geophys. Res. Lett., 39, L10203 (2012). 5 M. Gacesa, N. Lewkow and V. Kharchenko, "Non-thermal production and escape of OH from the upper atmosphere of Mars". Icarus, 284, pp.90-96 (2017). 6 S. Raghuram, A. Bhardwaj, & M. Dharwan, “Model for Nitric oxide and its dayglow emission in the Martian upper atmosphere using NGIMS/MAVEN measured neutral and ion densities”. Icarus, 382, 115010 (2022). 7 CM. Western, PGOPHER: a program for simulating rotational, vibrational and electronic spectra. J Quant Spectrosc Radiat Transf., 186:221–42 (2017). 8 HJ. Werner, PJ. Knowles, G. Knizia, FR. Manby, M. Schütz, Molpro: a general purpose quantum chemistry program package. J Chem Phys., 2:242–53 (2011). 9 RJ. LeRoy, "LEVEL: A computer program for solving the radial Schrödinger equation for bound and quasibound levels." J Quant Spectrosc Radiat Transf., 186:167–78 (2017). 10 J. W. Cooley, "An improved eigenvalue corrector formula for solving the Schrödinger equation for central fields," Math. Comput., vol. 15, no. 76, pp. 363–374, (1961).

TROPOMI Monitoring of NO2 Sources and Spread during the Beirut 2020 Seaport Ammonium Nitrate Explosion Nayla El-Kork1,2, Ashraf Farahat31Space and Planetary Science Center, Khalifa University,P.O. Box 127788, Abu Dhabi, United Arab Emirates;nayla.elkork@ku.ac.ae 2Department of Physics, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates;3Department of Physics, College of Engineering and Physics, King Fahd University of Petroleum, & Minerals, Dhahran 31261, Saudi Arabia.; ashraf.farahat@kfupm.edu.sa Ammonium nitrate (NH₄NO₃) is a white crystalline solid chemical compound consisting of ions of ammonium and is commonly used as a high-nitrogen garden and farm fertilizer. Ammonium nitrate can trigger explosions if exposed to a temperature above 190 °C. More than thirty ammonium nitrate accidents have occurred since the beginning of the 19th century, including explosions in the United Kingdom (1916), Germany (1921), the United States (1942, 1947, and 2013), France (2001), and China (2015). The most recent massive explosion occurred on August 4, 2020, in Beirut, Lebanon. The explosion killed over 200 people, injured about 7,000, damaged significant properties in Beirut, and loaded large amounts of particulate matter, dust, and toxic gases into the atmosphere. In this work, we use NO2 measurements from the Level 2 NO2 TROPOspheric Monitoring Instrument (TROPOMI), onboard S5P (100 – 700 nm) to investigate the generation of the toxic NO2 gas during the Beirut explosion. Interestingly a high NO2 emission over Beirut was observed from 28 July – 3 August 2020, a few days before the Beirut blast, with the highest emission on 28 July. This high NO2 background is attributed to many reasons: vehicle and ship emissions and the armed conflict in Syria. To confirm the possible effects of vehicles and ships in increasing NO2 loading in the atmosphere, the NO2 emission from Cairo, Egypt (known for its high population and high traffic volume); Nicosia, Cyprus (known for its low population and low traffic volume); and Suez Canal, Egypt (known for its high ship traffic and high traffic volume) are compared to Beirut NO2 emissions. Meanwhile, to understand the spatiotemporal distribution of NO2 (before, during, and after the explosion), the emission is examined in seven locations with four coastal (Beirut, Jounieh, Batron, and Tripoli) and three inland cities (Ehden, Baalbek, and Ain El Bnaiyyeh) in Lebanon. Results indicate that although NO2 was emitted during the Beirut blast, its amount was not significantly high, and it only affected some of the coastal locations within 20 – 25 km of Beirut, while it did not seem to affect the inland regions. The reported NO2 emission from the explosion could be overestimated, as there is an already high NO2 background in Beirut from vehicles, ships, and the armed conflict in Syria.

A four-dimensional-potential energy surface (4D-PES) of the atmospherically relevant CO2–O2 van der Waals complex is generated using ab initio methodology. Induced complexation shifts and second virial coefficient are also presented.

The adiabatic potential energy curves of the low lying electronic states of the Be halide anions BeX

We investigate the electronic structure of the molecule LaNa in Λ and Ω representations. The transition (1)0+–(2)0+ seem suitable for the laser cooling of this molecule. Two lasers are sufficient; however additional pumping lasers can be used, if needed.

The ground and excited electronic states of the diatomic molecules CaCs and CaNa have been investigated by implementing the ab initio CASSCF/(MRCI + Q) calculation. The potential energy curves of the doublet and quartet electronic low energy states in the representation

We report an ab initio study on the rovibronic spectroscopy of the closed-shell diatomic molecule phosphorous mononitride, PN. The study considers the nine lowest electronic states, X 1Σ+, A 1Π, C 1Σ−, D 1Δ, E 1Σ−, a 3Σ+, b 3Π, d 3Δ and e 3Σ− using high level electronic structure theory and accurate nuclear motion calculations. The ab initio data cover 9 potential energy, 14 spin–orbit coupling, 7 electronic angular momentum coupling, 9 electric dipole moment and 8 transition dipole moment curves. The Duo nuclear motion program is used to solve the coupled nuclear motion Schrödinger equations for these nine electronic states and to simulate rovibronic absorption spectra of 31P14N for different temperatures, which are compared to available spectroscopic studies. Lifetimes for all states are calculated and compared to previous results from the literature. The calculated lifetime of the A1Π state shows good agreement with an experimental value from the literature, which is an important quality indicator for the ab initio A–X transition dipole moment., We report an ab initio study on the rovibronic spectroscopy of the closed-shell diatomic molecule phosphorous mononitride, PN.

For the alkali iodide molecules LiI, NaI, KI, and RbI, ab initio CASSCF/(MRCI+Q) calculations have been employed to investigate the adiabatic potential energy curves and the static dipole moment curves of the low-lying singlet and triplet electronic states in the representation 2S+1Λ(+/−). The spectroscopic constants Te, Re, ωe, Be, αe, the dipole moment μe, and the dissociation energies De have been computed for the bound states. Additionally, the percentage ionic character fionic around the equilibrium position of the ground state and the (2)1Σ+ state has been estimated. Using the canonical function approach, these calculations have been followed by a rovibrational calculation from which the rovibrational constants Ev, Bv, Dv, and the abscissas of the turning points Rmin and Rmax for the investigated bound states are calculated.

The spectroscopic and ro-vibrational constants, FCFs and r-centroids have been evaluated in the present study for A2Π1/2–X2Σ, A2Π3/2–X2Σ, B2Σ–X2Σ, E2Π1/2–X2Σ, E2Π3/2–X2Σ, F2Σ–X2Σ, and L2Π–X2Σ band systems of the barium deuteride (BaD) molecule by adopting a reliable numerical integration procedure. The physical and astrophysical significances of the evaluated FCFs and r-centroids are discussed for all these band systems. The effect of vibration rotation interaction (VRI) on FCFs for the bands of the chosen band systems of BaD molecule is also studied. It is found from the results that the effect of VRI on FCFs is not so significant for the rotational quantum number (J) up to J = 50. For higher values of J like J = 100, there is a slight change in the value of FCFs due to the VRI effect.

The electronic structure of BeSe and BeTe molecules has been investigated using the ab initio CASSCF/(MRCI + Q) method at the spin-free and spin-orbit level. The potential energy curves, the permanent dipole moment, the spectroscopic constants Te, Re, ωe, and Be, and the dissociation energy De are determined in addition to the vertical transition energy Tv. The molecules' percentages of ionic character are deduced, and the trends of the spectroscopic constants of the two molecules are compared and justified. A ro-vibrational study is performed using the canonical function approach to calculate the constants Ev, Bv, and Dv and the turning points Rmin and Rmax. All the ground-state vibrational levels have also been investigated. The radiative lifetimes of vibrational transitions among the electronic ground states are also discussed. The results for BeSe have been compared with the previously published data while those for BeTe molecules are presented here for the first time.

Due to the lack of the electronic structure of NaBr and KBr diatomic molecules, a systematic investigation of the electronic structure of these molecules was performed using ab initio CASSCF/(MRCI + Q) calculations. The adiabatic potential energy curves of the low-lying singlet and triplet electronic states in the representation 2s+1Ʌ(+/−) of NaBr and KBr molecules have been investigated. The spectroscopic constants Te, Re, ωe, Be, α e , the dipole moment µe, and the dissociation energies De were calculated for the bound states in addition to the percentage ionic character fionic around the equilibrium position of two electronic states. Moreover, the static and the transition dipole moment curves have been calculated. The nuclear motion study has been performed using the canonical functions approach that allowed the determination of various rovibrational constants Ev, Bv, Dv and the abscissas of the turning points Rmin and Rmax for the investigated bound states. The investigated data are in a very good agreement with those given in literature. These results provide effective routes for many industrial applications and for the formation of cold alkali halide molecules in the low-lying vibrational states via experimental techniques.

Due to the absence of the electronic structure of the YP molecule and its ions in literature, this work is conducted via an ab initio Complete Active Space Self Consistent Field and the Multi-Reference Configuration Interaction with Davidson correction calculation (CASSCF/MRCI + Q) to investigate the low–lying electronic states of these molecules. Adiabatic potential energy curves (PECs) along with static dipole moment (DM) curves for 27, 24, and 21 low-lying electronic states in the representation of 2s+1Λ(+/−) for YP, YP+, and YP- molecules have been investigated, respectively. For the low-lying electronic states of the YP molecule and their anion and cation, the spectroscopic constants Re, Te, ωe, ωexe, Be, De are provided. The rovibrational constants Ev, Bv, Dv, and the abscissa of turning points Rmin and Rmax (up to vibrational level v = 37) are calculated using the canonical functions approach and referring to the calculated data from the PECs. Perturbation theory method is also used to compare our data's validity, as no results are presented in the literature for these molecules.

The potential energy curves of the low-lying electronic states of the SrX (X = Li, Na, K) molecules have been investigated by using the ab initio CASSCF/(MRCI + Q) calculation. For the considered electronic states the spectroscopic constants Te, ωe, Be, Re, αe, De the static and transition dipole moment curves, and the Franck-Condon factor (FCF) have been calculated. The study of the nuclear motion using the canonical functions approach allowed to determine different vibrational constants Ev, Bv, Dv and the turning points Rmin and Rmax up to the vibrational level v = 105. The comparison of the investigated data shows a very good agreement with those given in literature. These results have a great significance to experimentalists as they provide efficient routes to form cold alkali and alkaline earth molecules in low-lying vibrational states via experimental techniques.

The potential energy curves for the molecules MgK, MgRb and MgCs have been computed by using the ab initio CASSCF/ (MRCI + Q) calculation. For the considered electronic states the static and transition dipole moment curves have been calculated along with the Franck-Condon factor (FCF), the spectroscopic constants T e , ω e , ω e x e , B e , R e , and the fraction of ionic character. By using the canonical functions approach, the ro-vibrational constants E v , B v , D v and the abscissas of the turning points R min , and R max , have been calculated. For these molecules, more than 109 electronic states have been investigated in the present work. These results have great significance to experimentalists as they provide efficient routes to form cold alkali and alkaline earth molecules.

By the use of the ab initio CASSCF/(MRCI+Q) calculations in the representation

Adiabatic potential energy curves of the 28 low-lying doublet and quartet electronic states in the representation 2s+1Λ(±) of the zinc monofluoride molecule are investigated using the complete active space self-consistent field (CASSCF) with multi-reference configuration interaction (MRCI) method including single and double excitations with the Davidson correction (+Q). The internuclear distance Re, the harmonic frequency ωe, the static and transition dipole moment μ, the rotational constant Be, and the electronic transition energy with respect to the ground state Te are calculated for the bound states. The transition dipole moment between some doublet states is used to determine the Einstein spontaneous A21 and induced emission [Formula: see text] coefficients, as well as the spontaneous radiative lifetime τspon, emission wavelength λ21, and oscillator strength f21. The ground state ionicity qionicity and equilibrium dissociation energy DE,e are also computed. The comparison between the values of the present work and those available in the literature for several electronic states shows very good agreement. Twenty-three new electronic states have been studied in the present work for the first time.

Based on the complete active space self consistent field (CASSCF) method with multi-reference configuration interaction MRCI calculations including single and double excitations with Davidson correction (+Q), twenty three low lying electronic states in the 2s+1Λ(±) representation of the zinc monochloride ZnCl molecule are investigated considering 7 and 9 valence electrons. The internuclear distance Re, the harmonic frequency ωe, the permanent dipole moment μ, the rotational constant Be and the electronic transition energy with respect to the ground state Te are calculated for the bound states. The transition dipole moment between some doublet states is used to determine the Einstein spontaneous A 21 and induced emission B 21 ω coefficients, the spontaneous radiative lifetime τ spon , the emission wavelength λ 21 , the oscillator strength f 21 and the line strength S 21 . The fraction of the ground state ionic character f and equilibrium dissociation energy DE,e are also computed. Using the canonical function approach, the eigenvalues Ev, the rotational constants Bv, the centrifugal distortion constants Dv and the abscissas of the turning points Rmin and Rmax of the zinc monohalide molecules ZnX (X: F, Cl, Br, I) are calculated. The comparison between the values of the present work and those available in the literature for several electronic states shows good accordance.

The potential energy curves for the 45 singlet, triplet, and quintet electronic states in the representation 2s+1Λ(+/-) of the BF molecule have been investigated using the complete active space self-consistent field (CASSCF) method with multireference configuration interaction (MRCI). The internuclear distance Re, the harmonic frequency ωe, the static dipole moment μ, the rotational constants Be, and the electronic transition energy with respect to the ground state Te have been calculated for the considered electronic states. The comparison between the values of the present work and those available in the literature for several electronic states shows a very good agreement. Twelve electronic states of BF molecule are reported here for the first time that are not yet observed experimentally.

The electronic structure of the alkali hydride anions (LiH-, NaH-, and KH-), has been investigated via ab initio CASSCF/(MRCI + Q) and R-Matrix method calculations. Comparison between the results of the two calculation methods show that the pure bound state method may be unsuitable for the calculation of the electronic states of LiH- molecule, as the potential energy curves that it presents may be spurious. The adiabatic potential energy curves and the dipole moment curves of the low-lying electronic states of alkali hydride anionic molecules are investigated in the representation 2s+1Ʌ(+/-) where the percentage ionic character fionic around the equilibrium position of the ground state X2Σ+ has been calculated. Additionally, the spectroscopic constants Te, Re, ωe, Be, the dipole moment µe, and the dissociation energy De were computed for the bound states of the two molecules NaH- and KH-. The transition dipole moment curves for the lowest 2Σ+– 2Π transition have been also presented along with their Franck-Condon factor (FCF). A rovibrational study has been performed using the canonical functions approach in order to study the nuclear motion and find the rovibrational constants for the ground and several excited states. The diagonal Franck-Condon factor f00 may provide efficient routes for the formation of cold and ultracold molecules.

International audience; Near-Field Optical Microscopy is a valuable tool for the optical and topographic study of objects at a nanometric scale. Nanoparticles constitute important candidates for such type of investigations, as they bear an important weight for medical, biomedical, and biosensing applications. One, however, has to be careful as artifacts can be easily reproduced. In this study, we examined hybrid nanoparticles (or nanohybrids) in the near-field, while in solution and attached to gold nanoplots. We found out that they can be used for wavelength modulable near-field biosensors within conditions of artifact free imaging. In detail, we refer to the use of topographic/optical image shift and the imaging of Local Surface Plasmon hot spots to validate the genuineness of the obtained images. In summary, this study demonstrates a new way of using simple easily achievable comparative methods to prove the authenticity of near-field images and presents nanohybrid biosensors as an application.

By using the Rayleigh-Schrödinger perturbation theory the rovibrational wave function is expanded in terms of the series of functions ϕ0,ϕ1,ϕ2,…ϕn, where ϕ0 is the pure vibrational wave function and ϕι are the rotational harmonics. By replacing the Schrödinger differential equation by the Volterra integral equation the two canonical functions α0 and β0 are well defined for a given potential function. These functions allow the determination of (i) the values of the functions ϕι at any points; (ii) the eigenvalues of the eigenvalue equations of the functions ϕ0,ϕ1,ϕ2,…ϕn which are, respectively, the vibrational energy Ev, the rotational constant Bv, and the large order centrifugal distortion constants Dv,Hv,Lv….. Based on these canonical functions and in the Born-Oppenheimer approximation these constants can be obtained with accurate estimates for the low and high excited electronic state and for any values of the vibrational and rotational quantum numbers v and J even near dissociation. As application, the calculations have been done for the potential energy curves: Morse, Lenard Jones, Reidberg-Klein-Rees (RKR), ab initio, Simon-Parr-Finlin, Kratzer, and Dunhum with a variable step for the empirical potentials. A program is available for these calculations free of charge with the corresponding author.

The theoretical investigation of the potential energy curves, in the representation 2s+1Λ(+/-), of the 27 low-lying Doublet and Quartet electronic states of the BP+ molecular ion has been performed with the methods in quantum chemistry, the Complete Active Space Self Consistent Field (CASSCF) and the Multireference Configuration Interaction (MRCI) calculations. The harmonic vibrational frequency ωe, the inter-nuclear distance at equilibrium Re, the rotational constant Be, the electronic energy with respect to the minimum ground state energy Te, and the permanent dipole moment have also been calculated. Twenty-three new electronic states have been investigated here for the first time. The comparison between the values of the present work and those available in the literature for several electronic states shows a good agreement. These investigated data can be a conducive to further work on BP+ molecular ion in both experimental and theoretical research.

The Complete Active Space Self Consistent Field (CASSCF) with Multi Reference Configuration Interaction (single and double excitation with Davidson correction) MRCI + Q method has been used to investigate the potential energy curves of the 17 low-lying triplet electronic states of the molecule BP. The harmonic vibrational frequency ωe, the inter-nuclear distance at equilibrium Re, the rotational constant Be, the electronic energy with respect to the minimum ground state energy Te, and the permanent dipole moment have been also calculated. A literature review shows a strong correlation between our investigated data and those previously published either theoretically or experimentally. This work introduces, for the first time, a study of 14 new electronic states. Our spectroscopic data can be a conducive to further work on BP molecule in both experimental and theoretical research.

Complete Active Space Self Consistent Field (CASSCF) with Multireference Configuration Interaction (MRCI) and Rayleigh-Schrodinger Perturbation Theory (RSPT2-RS2) methods have been used to investigate the potential energy curves for the 12 low-lying singlet and triplet electronic states in the representation 2s+1Λ(+/-) of the molecule BaS with Davidson corrections. The harmonic frequency we, the internuclear distance Re, the electronic energy with respect to the ground state Te, the rotational constants Be and the permanent dipole moment have been calculated for these electronic states. The eigenvalues Ev, the rotational constants Bv, the centrifugal distortion constant Dv and the abscissas of the turning points Rmin and Rmax have been investigated using the canonical functions approach. Nine new electronic states have been investigated here for the first time. The comparison between the values of the present work and those available in the literature for several electronic states shows a good agreement.

By the use of the ab initio CASSCF/(MRCI+Q) calculations in the representation 2s+1Λ(+/−), the adiabatic potential energy curves and the dipole moment curves of the low lying states of the alkaline earth hydride anions (MgH−, CaH−, SrH− and BaH−) have been investigated in their singlet and triplet multiplicities. The spectroscopic parameters Te, Re, ωe, Be, αe, the dipole moment μe, and the dissociation energy De have been also calculated for the bound states of the considered molecules. In addition, a systematic investigation of the transition dipole moment curves for the lowest 1Σ+-1Π transitions has been done along with the Franck-Condon factor (FCF) corresponding to the X1Σ+-(1)1Π transition. Using the canonical function approach, a rovibrational study has been performed for finding the rovibrational constants Ev, Bv, Dv and the turning points Rmin and Rmax for the ground and different excited bound state. Efficient routes may be achieved via the diagonal FCF for the formation of cold and ultracold alkaline earth hydride anions. PACS No 31.10. + z, 31.15.A, 31.15.vn, 31.50.Df.

The adiabatic potential energy curves and the static dipole moment curves of the low-lying singlet and triplet electronic states in the representation 2s+1Λ(+/−) of the five alkali chloride molecules (LiCl, NaCl, KCl, RbCl and CsCl) have been investigated via ab initio calculations using the state averaged complete active space self consistent field followed by the Multi-reference single and double configuration interaction method with Davidson correction CASSCF/(MRCI + Q). For the molecules under consideration, the spectroscopic constants T e, R e, ω e and B e, the dipole moment μ e, and the dissociation energy D e have been calculated for the bound states along with the percentage ionic character f ionic around the equilibrium position of the ground state. Moreover, the transition dipole moment curves of the X1∑+–(2)1∑+ and X1∑+–(1)1Π transitions have been investigated for the five alkali chloride molecules. A rovibrational calculation was carried out using the canonical functions approach in order to determine the rovibrational constants E v, B v and D v and the abscissas of the turning points R min and R max for the investigated bound states.

Atomic and molecular data are at the origin of the atmospheres of planetary and stellar objects discoveries. Based on the laboratory astrophysics and the computational molecular spectroscopy, the interpretation of this data can give the chemical compositions and temperatures of these astrophysical systems. The detection and the identification of the SiN radical in the interstellar medium has drawn the attention to the gas phase chemistry and the evidence of a link between the interstellar chemistry of silicon and that of nitrogen. The quantum chemistry methods used to predict the spectroscopic properties of the SiN molecule can be calibrated with some available experimental results. In order to obtain reliable theoretical data that may help in the interpretation of interstellar or laboratory spectra concerning the SiN molecule, we performed theoretical calculation of 31 low-lying electronic state, below 66000 cm−1, of the molecule SiN by using the Complete Active Space Self Consistent Field (CASSCF) method followed by the Multi Reference Configuration Interaction with Davidson correction MRCI+Q. The potential energy along with the dipole moment curves of these states have been calculated along with the spectroscopic constants Re, ωe, Be, and Te. The Rotation-vibration lines for the considered electronic states of SiN molecule were obtained by direct solution of the nuclear motion Schrödinger equation using the canonical approach with program Rovib-1. By comparing our investigated values of the calculated vibrational energy Ev, the rotational constant Bv and the turning points Rmin and Rmax. with those available in literature shows a very good agreement. To the best of our knowledge nine new electronic states have been studied here for the first time that have not been observed yet.

The quantitative distribution of the molecular abundances in the universe is a classical problem in astronomy, astrophysics and cosmo-chemistry. Astrophysicists are interested in determining the abundances of molecular species in order to: (1) Know the primordial composition of the solar system, and its relation to the past and present composition of the earth. (2) Have a complete understanding of physical and chemical processes taking place in the stellar atmospheres and the interstellar medium (3) Test the hypotheses that have been proposed for element formation. To investigate the presence of astronomical sources, experimental astrophysicists usually study the wavelength and intensity of light that they emit. Many diatomic molecular species are present in various astrophysical sources, however, the theoretical studies on such species are not enough and information is missing in that area. Knowledge of the electronic structure, Franck-Condon factors (FCFs), and other related quantities for a band system of a diatomic molecule is essential to arrive at its astrophysically significant parameters such as kinetics of the energy transfer, radiative lifetimes, band intensity, vibrational temperature, etc. In this view, the spectroscopic and ro-vibrational constants, FCFs of several electronic states of the diatomic molecule SiS electronic have been evaluated in this work. We performed theoretical calculation of the low-lying electronic state, of the molecule SiS by using the Complete Active Space Self Consistent Field (CASSCF) method followed by the Multi Reference Configuration Interaction with Davidson correction MRCI+Q. The potential energy along with the dipole moment curves of these states have been calculated along with the spectroscopic constants Re, ωe, Be, and Te. Additionally, the Rotation-vibration lines for the considered electronic states were obtained by direct solution of the nuclear motion Schrödinger equation using the canonical approach with program Rovib-1

The potential energy curves of the molecule LaO have been calculated. Multireference CI calculations were performed. The harmonic frequency ωe, the internuclear distance re, the electronic energy with respect to the ground state Te and the permanent dipole moment have been calculated for 19 states where 13 states have been studied for the first time. By using the canonical functions approach, the eigenvalues Ev, the constant Bv and the abscissas of the turning points rmin and rmax have been calculated. The comparison of these values to the results available in the literature shows a very good agreement.

Via CASSCF/MRCI and RSPT2 calculations (single and double excitation with Davidson correction) the potential en- ergy curves of 20 electronic states in the representation 2S+1Λ（±）of the molecule SiO have been calculated. By fitting these potential energy curves to a polynomial around the equilibrium internuclear distance re, the harmonic frequency ωe, the rotational constant Be, and the electronic energy with respect to the ground state Te have been calculated. For the considered electronic states the permanent dipole moment μ have been plotted versus the internuclear distance r. Based on the canonical functions approach, the eigenvalues Ev, the rotational constant Bv and the abscissas of the turning points rmin and rmax have been calculated. The comparison of these values to the experimental and theoretical results available in the literature is presented. In the present work 8 higher electronic states have been studied theoretically for the first time.

A theoretical investigation for the feasibility of laser-cooling is performed through the calculation of accurate potential energy curves, static dipole moments, spectroscopic constants and rovibrational calculations for 24, 26 and 27 highly excited electronic states for BeF, CaF and MgF molecules respectively. In order to understand the electronic structure of their lowest lying electronic states and to learn the characteristic behavior of their chemical bonding, a high level of calculation is realized by using the complete active space self-consistent field (CASSCF) with multi-reference configuration interaction MRCI method including single and double excitations with Davidson correction (+Q) for the three considered molecules. The comparison between the values of the present work and those available in the literature for several electronic states shows a good agreement. Fifty new excited electronic states have been investigated, in the present work, for the first time for the three studied molecules.

The potential energy curves have been investigated for the 40 lowest electronic states in the 2s+1Λ(±)representation below 25000 cm-1 of the molecule NiO via CASSCF, MRCI (single and double excitation with Davidson correction) and CASPT2 methods. The harmonic frequency ωe , the internuclear distance re, the rotational constant Be, the electronic energy with respect to the ground state Te, and the permanent dipole moment μ have been calculated. By using the canonical functions approach, the eigenvalues Ev, the rotational constant Bv and the abscissas of the turning points rmin and rmax have been calculated for the considered electronic states up to the vibration level v = 12. Eleven electronic states have been studied theoretically here for the first time. The comparison of these values to the theoretical and experimental results available in literature shows a very good agreement.

We demonstrate how optical waveguides can serve as a high resolution illumination source to image hybrid nano-objects in near field optical microscopy. Nanohybrid particles deposited on the surface of glass waveguides are imaged in terms of topography, scattering and fluorescence.

The potential energy curves of the molecule LiCs have been calculated for the 55 low-lying electronic states in the Ω-representation. Using an ab initio method the calculation is based on a nonempirical pseudo-potential in the interval 3.0ao≤ R ≤ 40.0ao of the internuclear distance. The spin–orbit effects have been taken into account through a semi-empirical spin–orbit pseudo-potential added to the electrostatic Hamiltonian with Gaussian basis sets for both atoms. The spectroscopic constants have been calculated for 39 states and the components of the spin–orbit splitting have been identified for the states (2, 5)3Π and (1)3Δ. The comparison of the present results with those available in literature shows good agreement, while the other results, to the best of our knowledge, are given here for the first time.