An accurate description of the ground and excited states of CH

Καλέμος, Απόστολος; Mavridis, Aristides; Metropoulos, Aristophanes

doi:10.1063/1.480285

Cited by 105 publications

(97 citation statements)

References 231 publications

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“…139 The above picture is corroborated by the atomic equilibrium and asymptotic CASSCF distributions r ϱ : 3s Ϫ from the Si 3s to 3p z resulting in a 3s3 p z hybrid orbital, with the synchronous transfer to that hybrid of 0.09e Ϫ from the 1s hydrogen function.…”

Section: Resultssupporting

confidence: 48%

An accurate description of the ground and excited states of SiH

Καλέμος

Mavridis

Metropoulos

2002

The Journal of Chemical Physics

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The astrophysical importance of the SiH radical has motivated significant experimental and theoretical work. However, only the X 2 ⌸ and A 2 ⌬ states of SiH have been extensively investigated experimentally, while the study of higher excited states is rather limited. From a theoretical point of view, most of the studies have been focused on spectroscopic and thermochemical quantities of the ground state. The lack of accurate spectroscopic parameters (r e ,D e , e , e x e ,␣ e ,D e ,T e ) pertaining to higher excited states was the driving force of the present work, in line with our previous study of the isovalent CH molecule ͓A. Kalemos, A. Mavridis, and A. Metropoulos, J. Chem. Phys. 111, 9536 ͑1999͔͒. Using the multireference configuration interaction approach coupled with very large correlation-consistent basis sets, we have constructed potential energy curves for 18 molecular states correlating to Si( 3 P,At the same level, the potential energy curve of the ground SiH ϩ state (X 1 ⌺ ϩ ) has also been constructed. We report total energies, dissociation energies, and the usual spectroscopic constants for 28 2 H and for all states studied. Most of our results are in excellent agreement with existing experimental values. In particular, we believe that our dissociation energy for the X state, D e ϭ73.28 kcal/mol, is the most reliable reported so far in the literature.

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Section: Resultssupporting

confidence: 48%

An accurate description of the ground and excited states of SiH

Καλέμος

Mavridis

Metropoulos

2002

The Journal of Chemical Physics

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“…In Table 13 we present equilibrium molecular constants (in cm −1 ) for the four lowest doublet electronic states of 12 CH, including the a 4 Σ − state for which the constants are taken from Kalemos et al (1999) and Lie et al (1973). These constants were used to compute the potential curves and the transition-moment matrix elements (see Sect.…”

Section: Equilibrium Constants and Partition Function 431 Equilibrmentioning

confidence: 99%

“…This molecule was first detected by Heurlinger & Hulthen (1919) and then studied by many scientists (see references in Kalemos et al 1999). This molecule has many valence and Rydberg states as reviewed by Vázquez et al (2007), but only the lower energy states are of interest for stellar astrophysics.…”

Section: Introductionmentioning

confidence: 99%

CH in stellar atmospheres: an extensive linelist

Masseron

Plez

Eck

et al. 2014

A&A

256

216

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The advent of high-resolution spectrographs and detailed stellar atmosphere modelling has strengthened the need for accurate molecular data. Carbon-enhanced metal-poor (CEMP) stars spectra are interesting objects with which to study transitions from the CH molecule. We combine programs for spectral analysis of molecules and stellar-radiative transfer codes to build an extensive CH linelist, including predissociation broadening as well as newly identified levels. We show examples of strong predissociation CH lines in CEMP stars, and we stress the important role played by the CH features in the Bond-Neff feature depressing the spectra of barium stars by as much as 0.2 mag in the λ = 3000−5500 Å range. Because of the extreme thermodynamic conditions prevailing in stellar atmospheres (compared to the laboratory), molecular transitions with high energy levels can be observed. Stellar spectra can thus be used to constrain and improve molecular data.

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“…The NH + ion has so far been much less studied than the neutrals NH or CH. Given that NH + and CH are isoelectronic molecules, one can get information from parallel studies of their analogous states (Kalemos et al 1999). It should be noted however that the order of the two first excited doublet states in CH and NH (Table 1).…”

Section: Introductionmentioning

confidence: 99%