Line Lists for LiF and LiCl in the X1Σ+ Ground State

Vibration–rotation line lists for 6LiF, 7LiF, 6Li35Cl, 6Li37Cl, 7Li35Cl, and 7Li37Cl in the X1Σ+ ground states have been prepared. The rovibrational energy levels have been calculated using potential energy surfaces determined by direct potential-fitting employing the rotational and rovibrational transition frequencies of all isotopologues, and required the inclusion of Born–Oppenheimer breakdown terms. Dipole moment functions calculated ab initio at the MRCI/aug-cc-pwCV5Z level have been used for line strength calculations. Partition functions for temperatures up to 5000 K have been calculated. LiF and LiCl are predicted to be present in the atmospheres of hot rocky exoplanets, brown dwarfs, and cool stars

Spectroscopic Constants and Line Positions for TiO Singlet States

consistent set of spectroscopic constants for the a1Δ,d1Σ+,b1Π,c1Φ, and f1Δ states of 48Ti16O has been determined from analysis of the b1Π–a1Δ,b1Π–d1Σ+,c1Φ–a1Δ, and f1Δ–a1Δ systems. Three Fourier transform emission spectra have been used for the analysis. New bands of the b1Π–a1Δ and c1Φ–a1Δ systems have been fitted. The first analysis of the c1Φ–a1Δ system using Fourier transform spectra is also provided. Extensive and improved line positions are measured. TiO is prominent in the spectra of oxygen-rich cool stellar objects and may be present in hot-Jupiter exoplanet atmospheres

Internal dynamics in SF6···NH3 observed by broadband rotational spectroscopy

The rotational spectra of SF$_{6}$$cdot$$cdot$$cdot$NH$_{3}$ isotopologues have been observed in a pulsed nozzle chirped pulse Fourier-transform microwave spectrometer in the frequency range 6.5-18.5 GHz. The spectrum of SF$_{6}$$cdot$$cdot$$cdot$$^{14}$NH$_{3}$ has been fitted to a Hamiltonian describing a symmetric top complex in which two symmetric top subunits undergo free internal rotation about a common symmetry axis. The distance between the centers of mass of the two monomers was found to be 4.15776(7) AA. Challenges associated with fitting textbar textit{m}textbar =1 transitions (correlating with textit{K} of free NH$_{3}$) for SF$_{6}$$cdot$$cdot$$cdot$$^{14}$ND$_{3}$ imply complicated internal dynamics occurs within the complex

LINE LISTS FOR LiF AND LiCl IN THE X1Σ+ STATE

Alkali-containing molecules are expected to be present in the atmospheres of exoplanets such as rocky super-Earthsfootnote{Phil. Trans. R. Soc. A textbf{372}, 20130087 (2014)} as well as in cool dwarf stars.footnote{Astrophys. J. textbf{519}, 793 (1999)} Line lists for LiF and LiCl in their textit{X}$^{1}$$Sigma$$^{+}$ ground states have been calculated using LeRoy’s LEVEL program.footnote{J. Quant. Spectrosc. Radiat. Transfer textbf{186}, 167 (2017)} The potential energy functions, including the effects of the breakdown of the Born-Oppenheimer approximation, are obtained by direct fitting the experimental infrared vibration-rotation and microwave pure rotation data with extended Morse oscillator potentials using LeRoy’s dPotFit program.footnote{J. Quant. Spectrosc. Radiat. Transfer textbf{186}, 179 (2017)} The transition dipole matrix elements and line intensities were obtained with LEVEL using a dipole moment function from a high level textit{ab initio} calculation

SPECTROSCOPY OF TiO SINGLET STATES

TiO is a molecule of considerable astronomical importance. It is present in the atmospheres of oxygen-rich low-mass stellar objects. Three Fourier transform emission spectra have been used to determine improved and consistent spectroscopic constants of the a$^1$$\Delta$, b$^1$$\Pi$, d$^1$$\Sigma$$^+$, c$^1$$\Phi$ and f$^1$$\Delta$ states of TiO by fitting the b$^1$$\Pi$-a$^1$$\Delta$, b$^1$$\Pi$- d$^1$$\Sigma$$^+$, c$^1$$\Phi$-a$^1$$\Delta$ and f$^1$$\Delta$-a$^1$$\Delta$ systems. This analysis provides the most extensive fit of the TiO singlet states. New bands of the b$^1$$\Pi$-a$^1$$\Delta$ and c$^1$$\Phi$-a$^1$$\Delta$ systems have been measured and an extensive list of line positions will be published

(CH3)3N···AgI and H3N···AgI studied by broadband rotational spectroscopy and ab initio calculations

The pure rotational spectra of 8 isotopologues of H$_{3}$N$cdot$$cdot$$cdot$AgI and 6 isotopologues of (C{H$_{3}$})$_{3}$N$cdot$$cdot$$cdot$AgI were measured in a chirped pulse Fourier-transform microwave spectrometer. The complexes were synthesized in a molecular beam from a gas sample containing H$_{3}$N or (C{H$_{3}$})$_{3}$N and CF$_{3}$I precursors diluted in argon. Laser ablation was used to introduce silver atoms to the gas phase. The rotational constant textit{B}$_{0}$, centrifugal distortion constants textit{D}$_{J}$ and textit{D}$_{JK}$, and the nuclear quadrupole coupling constant $chi$$_{aa}$(I) have been determined for (C{H$_{3}$})$_{3}$$^{14/15}$N$cdot$$cdot$$cdot$$^{107/109}$AgI, (C{D$_{3}$})$_{3}$N$cdot$$cdot$$cdot$$^{107/109}$AgI, H$_{3}$$^{14/15}$N$cdot$$cdot$$cdot$$^{107/109}$AgI and D$_{3}$N$cdot$$cdot$$cdot$$^{107/109}$AgI by fitting the measured transitions to a symmetric top Hamiltonian. The spectroscopic constants (textit{B}$_{0}$+ textit{C}$_{0}$), $Delta$$_{J}$ and $chi$$_{aa}$(I) have been determined for D$_{2}$HN$cdot$$cdot$$cdot$$^{107/109}$AgI through fits that employed a Hamiltonian appropriate for a very near prolate asymmetric rotor. Partial effective (textit{r}$_{0}$) and substitution (textit{r}$_{s}$) structures have been determined

ULTRAVIOLET AND INFRARED OSCILLATOR STRENGTHS FOR OH+

OH$^+$ is an important astrophysical species. OH+ has been detected in the interstellar medium by UV and terahertz spectroscopy. Following the recent analysis of OH$^+$ emission spectra,\footnote{Hodges, J. N., \& Bernath, P. F. Astrophys. J., 840.2 (2017) 81} empirical potential energy surfaces have been calculated for the A$^3$$\Pi$ and X$^3$$\Sigma$$^-$ states using the RKR method. Ab initio transition and dipole moment functions were calculated and together with the potential energy surfaces have been used to compute oscillator strengths using Le Roy’s LEVEL program.\footnote{Le Roy, R. J., J. Quant. Spectrosc. Radiat. Transf. 186 (2017) 167} The new oscillator strengths account for the Herman–Wallis effect, a rotational dependence in the vibrational wavefunction, and are now in good agreement with the measured lifetime.\footnote{M\"{o}hlmann, G. R., et al., Chem. Phys. 31.2 (1978) 273} The Herman–Wallis effect creates a 5\% difference in UV oscillator strengths by J'' = 15 and an 80\% difference in oscillator strengths by J'' = 10 in the IR. We recommend these new oscillator strengths be used to determine OH$^+$ column densities

Improved Ultraviolet and Infrared Oscillator Strengths for OH+

Molecular ions are key reaction intermediates in the interstellar medium. OH+ plays a central role in the formation of more complex chemical species and for estimating the cosmic ray ionization rate in astrophysical environments. Here, we use a recent analysis of a laboratory spectrum in conjunction with ab initio methods to calculate infrared and ultraviolet oscillator strengths. These new oscillator strengths include branch dependent intensity corrections, arising from the Herman–Wallis effect, that have not been included before. We estimate 10% total uncertainty in the UV and 6% total uncertainty in the IR for the oscillator strengths

Gas phase complexes of H₃N⋯CuF and H₃N⋯CuI studied by rotational spectroscopy and:Ab initio calculations: The effect of X (X = F, Cl, Br, I) in OC⋯CuX and H₃N⋯CuX

Complexes of H3N⋯CuF and H3N⋯CuI have been synthesised in the gas phase and characterized by microwave spectroscopy.</p

ULTRAVIOLET AND INFRARED OSCILLATOR STRENGTHS FOR OH+

OH$^+$ is an important astrophysical species. OH+ has been detected in the interstellar medium by UV and terahertz spectroscopy. Following the recent analysis of OH$^+$ emission spectra,\footnote{Hodges, J. N., \& Bernath, P. F. Astrophys. J., 840.2 (2017) 81} empirical potential energy surfaces have been calculated for the A$^3$$\Pi$ and X$^3$$\Sigma$$^-$ states using the RKR method. Ab initio transition and dipole moment functions were calculated and together with the potential energy surfaces have been used to compute oscillator strengths using Le Roy’s LEVEL program.\footnote{Le Roy, R. J., J. Quant. Spectrosc. Radiat. Transf. 186 (2017) 167} The new oscillator strengths account for the Herman–Wallis effect, a rotational dependence in the vibrational wavefunction, and are now in good agreement with the measured lifetime.\footnote{M\"{o}hlmann, G. R., et al., Chem. Phys. 31.2 (1978) 273} The Herman–Wallis effect creates a 5\% difference in UV oscillator strengths by J'' = 15 and an 80\% difference in oscillator strengths by J'' = 10 in the IR. We recommend these new oscillator strengths be used to determine OH$^+$ column densities