Astrophysical Molecules AlD and CaH: Transition Probabilities and Dissociation Energy

The Franck-Condon (FC) factors and r-centroids for the bands systemC ¹ Σ ⁺ → X ¹ Σ ⁺ of AlD and E ² Π → X ² Σ ⁺ of CaH have been evaluated by means of a reliable numerical integration procedure by using a suitable potential. The dissociation energy, D _e, for the electronic ground states of AlD and CaH have been estimated by the curve fitting method to the RKRV experimental potential curve turning out to be 3.01 eV and 2.32 eV, respectively. This revised version was published online in July 2006 with corrections to the Cover Date.     

Franck-Condon factors and r-centroids for certain band systems pf astrophysical molecule BeF

The Franck-Condon factors and r-centroids, which are very closely related to vibrational transition probabilities, have been evaluated by the more reliable numerical integration procedure for the bands of B ² Σ⁺ - X ² Σ⁺, C ²Σ⁺ - X ² Σ⁺ andC ² Σ⁺ - A ² Π_r systems of the astrophysical molecule BeF, using a suitable potential. This revised version was published online in July 2006 with corrections to the Cover Date.     

Astrophysically useful radiative transition parameters for?the?e1Π–X1Σ+ and 1Σ+–X1Σ+ systems of zirconium oxide

The zirconium oxide (ZrO) is well known for its astrophysical importance. The radiative transition parameters that include Franck-Condon (FC) factor, r-centroid, electronic transition moments, Einstein coefficient, band oscillator strengths, radiative life time and effective vibrational temperature have been estimated for e ¹Π–X ¹Σ⁺ and ¹Σ⁺–X ¹Σ⁺ band systems of ⁹⁰ZrO molecule for the experimentally known vibrational levels using RKR potential energy curves. A reliable numerical integration method has been used to solve the radial Schr?dinger equation for the vibrational wave functions of upper and lower electronic states based on the latest available spectroscopic data and known wavelengths. The estimated radiative transition parameters are tabulated. The effective vibrational temperatures of these band systems of ⁹⁰ZrO molecule are found to be below 4200 K. Hence, the radiative transition parameters help us to ascertain the presence of ⁹⁰ZrO molecule in the interstellar medium, S stars and sunspots.     

Franck-Condon factors and <Emphasis Type="Italic">r</Emphasis>-centroids for certain band systems of astrophysical molecules SrF and ScF

The Franck-Condon factors and r-centroids, which are very closely related to vibrational transition probabilities, have been evaluated by the more reliable numerical integration procedure for the bands of B ²∑⁺ − X ²∑⁺, F ²∑⁺ − X ²∑⁺ systems of SrF and C ¹∑⁺ − X ¹∑⁺, G ¹Π − X ¹∑⁺ systems of ScF molecules of astrophysical interest, using a suitable potential.     

Franck-Condon Factors and r-Centroids of Certain Band Systems of Astro Physical Molecules SO and TiO

The Franck-Condon (FC) factors (transition probabilities) and r-centroids have been evaluated by the reliable numerical integration procedure for the bands of the b1 Σ+ −x3 Σ− system of astrophysical molecule SO. Also for the bands of f1Δ − a1 Δ and e1 Σ+ − d1 Σ+ systems of astrophysical molecule TiO, the FC factors and r-centroids have been evaluated, using a suitable potential. This revised version was published online in July 2006 with corrections to the Cover Date.     

Presence of LaO, ScO and VO Molecular Lines in Sunspot Umbral Spectra

High-resolution Fourier Transform Spectrometer sunspot umbral spectra of the National Solar Observatory/National Optical Astronomy Observatory at Kitt Peak were used to detect rotational lines from 19 electronic transition bands of the molecules LaO, ScO and VO, in the wavenumber range of 11 775 to 20 600 cm⁻¹. The presence of lines from the following transitions is confirmed: A ² Π _r1/2 – X ² Σ ⁺(0, 0; 0, 1), A ² Π _r3/2 – X ² Σ ⁺(1, 0), B ² Σ ⁺ – X ² Σ ⁺(0, 0; 0, 1; 1, 0) and C ² Π _r1/2 – A′²Δ _r3/2(0, 0; 1, 1) of LaO; A ² Π _r3/2 – X ² Σ ⁺(0, 0), A ² Π _r1/2 – X ² Σ ⁺(0, 0) and B ² Σ ⁺ – X ² Σ ⁺(0, 0) of ScO; and C ⁴ Σ ⁻ – X ⁴ Σ ⁻(0, 1; 1, 0; 0, 2) and (2, 0) of VO. However, the presence of A ² Π _r3/2 – X ² Σ ⁺(0, 0) and C ² Π _r3/2 – A′²Δ _r5/2(0, 0; 1, 1) of LaO and C ⁴ Σ ⁻ – X ⁴ Σ ⁻(0, 0) of VO are found to be doubtful because the lines are very weak, and detections are difficult owing to heavy blending by strong rotational lines of other molecules. Equivalent widths are measured for well-resolved lines and, thereby, the effective rotational temperatures are estimated for the systems for which the presence is confirmed.     

Spectroscopic Studies on Astrophysically Interesting TaO TaS, ZrS and SiO+ Molecules

The true experimental potential energy curves for the electronic ground states of astrophysically important TaO, TaS, ZrS and SiO⁺molecules are constructed by using the Rydberg–Klein–Rees method as modified by Vanderslice et al. The ground state dissociation energies are determined by curve fitting techniques using the five parameters Hulburt-Hirschfelder (H-H) function. The estimated dissociation energies are 8.19 ± 0.17, 6.9 ±0.14, 5.89 ± 0.12 and 5.75 ± 0.12 eVfor TaO, TaS, ZrS and SiO⁺ respectively. These values are in good agreement with the literature values. The r-centriods and Franck–Condon factors (FC Factors) for the bands of K ² φ _5/2 - X ² Δ _3/2 (K-X) system of TaO, A-X ² Δ (A-X) and B-X ² Δ (B-X)systems of TaS, B ¹ Π - X¹ Σ⁺ (B-X) system of ZrS and B ²Σ⁺ - X² Σ⁺ (B-X) and A ² Π - X² Σ⁺ (A-X)systems of SiO⁺ molecules have been calculated. The Franck–Condon factors (FC factors) are evaluated by the approximate analytical methods of Jarmain and Fraser. The absence of the bands of these systems is explained. This revised version was published online in July 2006 with corrections to the Cover Date.     

Estimation of potential energy curves, dissociation energies, franck-condon factors and r-centroids of comet interesting molecules

The experimental potential energy curves for the different electronic states of molecules like CN, CO and CS observed in comets are constructed by using the Rydberg-Klein-Rees method as modified by Vanderslice et al. The ground state dissociation energies are determined by curve fitting technique using the five parameter Hulburt-Hirschfelder (H-H)function. The estimated dissociation energies are 7.63 ± 0.187, 10.95 ±0.224 and 7.27 ± 0.152 eV for CN, CO and CS respectively. These values are in good agreement with the literature values. Estimated dissociation energies of CN, CO and CS are used in the relation given by Gaydon and ionization potentials are evaluated for CO and CS molecules. The estimated ionization potentials are 13.92and 12.15 eV for CO and CS molecules respectively. The r-centroids and Franck-Condon factors (FC Factors) for the band system of a ³Π_r – X¹Σ⁺ (a – X) and A¹Π – X ¹Σ⁺ (A -X) of CN, A ²Π_i – X²Σ⁺ (A – X) and B²Σ⁺-X²Σ⁺ (B – X) of CO and a ³Π_r – X¹Σ⁺ (a – X) of CS molecules have been calculated employing an approximate analytical methods of Jarmain and Fraser and Nicholls and Jarmain. The absence of the bands in these systems are explained. This revised version was published online in July 2006 with corrections to the Cover Date.     

Spectrum variability of 25 Sextantis

Vibrational transition probabilities: namely, Franck-Condon factors andr-centroids, have been evaluated using an approximate analytical method for theB-A system of MgO. Morse potential energy curves forB ¹⁺ andA ¹ states of MgO have been constructed by use of the latest spectroscopic data. The value ofr-centroids for the band have been found to decrease linearly with the corresponding wavelength. We show results for six new bands in the umbral spectrum of the Sun.     

Transition probabilities and dissociation energy of astrophysical molecule CoH

The Franck-Condon (FC) factors (transition probabilities) and r-centroids have been evaluated by the reliable numerical integration procedure for the bands of the A ³ φ₄ →X ³ φ₄ system of astrophysical molecule CoH, using a suitable potential. The dissociation energy D ⁰ ₀ = 2.5 ± 0.05 eV for the electronic ground state of CoH has been estimated by fitting Hulburt-Hirschfelder function to the experimental potential energy curve, using the correlation coefficient. This revised version was published online in July 2006 with corrections to the Cover Date.     

r-Centroids and Franck-Condon factors of the CP,SiC, and CO+ molecules

Ther-centroids and Franck-Condon factors for the bands of theA ² –X ²⁺ of CP,C ³ –X ³ of SiC, andB ²⁺ –X ²⁺ of CO⁺ molecules have been determined. The Franck-Condon factors are evaluated by the approximate analytical method of Jarmain and Fraser. The absence of the bands in these systems is explained.     

Transition probabilities and dissociation energy of astrophysical molecule GeH

The Franck-Condon factors andr-centroids, which are very closely related to vibrational transition probabilities, have been evaluated by the more reliable numerical integration procedure for the bands of A ² Δ - X² π_r system of astrophysical molecule GeH, using a suitable potential. The dissociation energy for the electronic ground state of astrophysical molecule GeH has been estimated precisely as D ⁰ ₀ = 2.69 ± 0.05 eV by fitting the empirical potential function to the experimental potential energy curve using correlation coefficient. This revised version was published online in July 2006 with corrections to the Cover Date.     

Franck-condon factors and -centroids for certain band systems of astrophysical molecular ions CN+ and N+2

The Franck-Condon factors and r-centroids, which are very closelyrelated to relative vibrational transition probabilities, have beenevaluated by the more reliable numerical integration procedure forthe bands of c ¹ - a ¹ and f ¹ - a ¹ systems of CN ⁺ and C ^{2 +} _u- X ^{2 +} _g and D ² _g- A ² _u systems of N ⁺ ₂ molecular ions of astrophysical interest,using a suitable potential.     

Transition probabilities and dissociation energy of astrophysical molecule CrH

The Franck-Condon (FC) factors (transition probabilities) andr-centroids have been evaluated by the reliable numerical integration procedure for the bands of the A⁶⁺ X ⁶⁺ system of astrophysical molecule CrH, using a suitable potential. The dissociation energyD ₀ ⁰ = 2.3 eV for the electronic ground state of CrH has been estimated by fitting the Hulburt-Hirschfelder function to the experimental potential energy curve, using the correlation coefficient.     

Identification of SrF molecular lines in the spectrum of sunspot umbra

A high resolution spectrum of a sunspot umbra is used for identification of rotational lines due to (0, 0) band of the A ²Π–X ²Σ⁺ system and (0, 0), (1, 1), and (2, 2) bands of the B ²Σ⁺–X ²Σ⁺ system of the molecule SrF. The published sunspot umbral spectrum obtained with Fourier Transform Spectrometer and solar telescope of National Solar Observatory/National Optical Astronomy Observatory at Kitt Peak was used for the study. The new identification of more than 200 SrF lines in the umbral spectrum confirms that this molecule accounts for the majority of lines in the spectral range 15050 to 15360 cm⁻¹ and 17240 to 17300 cm⁻¹. Equivalent widths have been measured for well-resolved lines of these bands and the effective rotational temperatures have been estimated for which the presence is confirmed.     

Spectroscopic parameters for certain band systems of astrophysically important molecule: Yttrium oxide

The Franck–Condon (FC) factors and r-centroids are defined through elementary integrals that involve vibrational wave functions on which they depend in a sensitive manner. The FC factors and r-centroids have been evaluated by a reliable numerical integration procedure on the basis of RKR potential energy model, for the A²Π_3/2 ? X²Σ⁺, A²Π_1/2 ? X²Σ⁺ and B²Σ⁺ ? X²Σ⁺ band systems of the astrophysically important yttrium oxide molecule. RKR and Morse potential values have been generated for all the four electronic states of YO molecule. All of these three systems of YO show significant rotational independence.     

Occurrence of AlO Molecular Lines in Sunspot Umbral Spectra

Aluminium monoxide (AlO) is widely known for its astrophysical significance. An analysis of the prominent lines of the (2,3;3,2;3,4;4,5;4,3;5,6;6,7) bands of the B ²Σ⁺?X ²Σ⁺ transition with those of sunspot umbral spectral lines suggests that the AlO molecule appears to be a non-negligible component of sunspot umbrae. Results of a recent (2008) rotational analysis were used to carry out the study. The effective rotational temperature determined for the above lines in the sunspot umbral spectrum is found to be of the order of 2900 K. The radiative-transition parameters that include Franck–Condon (FC) factors, r-centroids, electronic-transition moment, Einstein coefficient, absorption–band oscillator strength, and radiative lifetime have been estimated for the experimentally known vibrational levels using the Rydberg–Klein–Rees (RKR) potential.     

YO molecule in the sun

Vibrational transition probabilities, namely Franck—Condon factors and -centroids have been evaluated by an approximate analytical method for the (A–X), (A–X), and (A–X) system of YO molecule. Morse potential energy curves forX ²⁺,A ²₂,A²₂, andA²₂, states of YO have been constructed using the latest spectroscopic data. The value of -centroids for the band have been found to decrease linearly with the corresponding wavelengths. We show results for two new transitions of (A–X) and (A–X) and five new bands of (A–X) of YO in the umbral spectrum of the Sun.     

Comet Hale–Bopp: Velocity Field Of Ions From Fabry-Pérot Imaging

Fabry-Pérot interferograms of comet Hale-Bopp were obtained on several nights in March and April 1997. For this purpose we utilized the 2-channel focal reducer of the Max-Planck-Institute for Aeronomy at the 2-m telescope of the Pik Terskol Observatory. Solid Fabry-Pérot etalons of resolving power 30000 were used in both channels of the focal reducer. The main aim of this study is to measure the velocities and abundances of OH⁺ and H₂O⁺, both ions closely related to the same parent molecule, H₂O. In the blue channel interferograms we identified several individual OH⁺ rotational lines of the A³Π_i - X³Σ⁻ (0-0) transition and measured their Doppler shifts. The target emissions in the red channel were the H₂O⁺ lines of the A²A₁ − X²B₁ (10-0) band. We found that the line of sight velocities, obtained from the Doppler shifted wavelengths of emissions in the comet are higher in sunward direction than in the plasma tail and do not exceed 20 km s^–1. The corresponding values, deprojected in antisolar direction, are consistent with predictions by magnetohydrodynamical models of the solar-wind-comet interaction, when one accounts for the extremely high gas production rate of comet Hale-Bopp. This revised version was published online in July 2006 with corrections to the Cover Date.     

RKRV Potential Energy Curves, Dissociation Energies, γ-Centroids And Franck-Condon Factors Of YO, CrO, BN, ScO, SiO And AlO Molecules

The potential energy curves for the electronic ground states of astrophysically important YO, CrO, BN, ScO, SiO and AlO molecules are constructed techniques using the five-parameter Hulburt-Hirschfelder function. The estimated dissociation energies are 7.235±0.15, 4.337 ± 0.09, 3.917 ± 0.09, 6.899 ± 0.14, 8.181 ± 0.17 and 5.202 ± 0.11 eV for YO, CrO, BN, ScO, SiO and AlO, respectively. The estimated D₀ values are in reasonably good agreement with literature values. The r-Centroids and Franck-Condon factors for the bands of B^{2 +} – X^{2 +} of YO, B⁵ –X⁵ > of CrO, A³ – X³ of BN, B^{2 +} –X^{2 +} of ScO, E^{1 +} – X^{1 +} of SiO and D^{2 +} – X^{2 +} and B^{2 +} –X^{2 +} of AlO molecules have been determined. The Franck-Condon factors are evaluated by the approximate analytical method of Jarmain and Fraser. The absence of the bands in these systems is explained.