Franck–Condon factors and r-centroids for a number of band systems of the astrophysical molecule AlF

Kumar, K. Balachandra; Rajamanickam, N.; Bagare, S. P.; Gómez, M. Fernández; González, Juan Jesús López

doi:10.1016/s0927-6505(03)00149-x

Cited by 8 publications

(3 citation statements)

References 14 publications

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“…The radiative lifetimes of the excited states and Einstein coefficients of the A 1 Π-X 1 Σ + transition were also computed. Kumar et al [20] evaluated the FCFs and r-centroids using a numerical integration procedure for the systems of B…”

Section: Introductionmentioning

confidence: 99%

Theoretical study on the transition properties of AlF

Zhang¹,

Ji²,

Ru³

et al. 2022

Chinese Phys. B

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Potential energy curves of the X1Σ+ and A1Π states of the AlF molecule are studied through the combination of the multi-reference configuration interaction (MRCI) approach and Davidson corrections (MRCI+Q). The AWCV5Z basis set is employed in the calculations. The transition dipole moments (TDMs) of the A1Π ↔ X1Σ+ transition are explored based on the AWCV5Z basis set and (4, 2, 2, 0) active space. The Schrödinger equation is solved via the LEVEL 8.2 program, and the vibrational levels and rotational constants of the X1Σ+ and A1Π states are calculated. It is shown that the AlF molecule has high diagonal Franck–Condon factors (f 00 = 0.9949 and f 11 = 0.9854) and large Einstein coefficients for the transition of A1Π (ν′ = 0) ↔ X1Σ+ (ν″ = 0). In addition, the radiative lifetimes of the vibrational levels are close to 10−9 s for the A1Π state. The line intensities of the A1Σ (ν′ = 4 – 15) ↔ X1Σ+ (ν″ = 0) transitions are also calculated. The calculated TDMs and transition probabilities in this work are credible and provide some guidance for the study of similar transitions, particularly for exploring interstellar space.

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Section: Introductionmentioning

confidence: 99%

Theoretical study on the transition properties of AlF

Zhang¹,

Ji²,

Ru³

et al. 2022

Chinese Phys. B

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“…Also, Highberger et al (2001) reported in 2001 the detection of AlF in the circumstellar envelope of the so-called Egg Nebula (CRL 2688). Following the suspected presence of AlF in umbral spectra suggested by the observations of Wöhl (1971) and using the significant values of transition probabilities computed by Murty (1977), Joshi et al (1982) and Balachandra Kumar et al (2002Kumar et al ( , 2003Kumar et al ( , 2004, Bagare et al (2006) have conducted a fresh search for the presence of AlF lines with the high resolution FTS sunspot umbral spectra. They reported without doubt that the bands of AlF are present in the umbral spectra.…”

Section: Introductionmentioning

confidence: 99%

Collision induced rotational excitation of AlF (X 1Σ+) by para-H2 (j=0)

Gotoum

Hammami

Owono

et al. 2011

Astrophys Space Sci

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Rotational excitation cross sections and rate coefficients of AlF collisions with para-H 2 are computed at low temperature, i.e., for T ≤ 70 K. Prior to collisional calculations, a four-dimensional (4D) potential energy surface (PES) for the AlF-H 2 system is calculated at the ab initio Coupled-Cluster level of the theory with an aug-cc-pVQZ Gaussian basis set. This 4D-PES is further reduced to a twodimensional (2D) PES based on the considerations related to collisional studies with para-H 2 . The [Al-F] and [H-H] bond lengths are frozen at their experimental equilibrium value r e = 1.654369 bohr and r e = 1.4011 bohr respectively. The interaction energy presents a global minimum located ∼63 cm −1 below the AlF-H 2 dissociation limit. With this PES, cross sections are determined in the Close-Coupling (CC) approach and rate coefficients are inferred by averaging the cross sections over a Maxwell-Boltzman distribution of kinetic energies. These quantities are significantly magnified in comparison with their AlF-He counterparts. The already observed propensity towards J = 1 transitions for AlF-He remains.

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“…In view of the astrophysical significance of AlF transitions, the Franck -Condon Factors (FCF), which are transition probabality parameters, were computed by Murty (1977) for C -A transition, by Joshi et al (1982) for A -X transition, and by Balachandra Kumar, Rajamanickam, and Bagare (2002); Balachandra Kumar et al (2003); Balachandra Kumar, for 13 electronic transitions of AlF. The significant values of transition probabilities reported by these authors, and the suspected presence suggested by the observations of Wöhl (1971), called for a fresh search for the presence of AlF lines in umbral spectra.…”

Section: Introductionmentioning

confidence: 99%

Identification of AlF Molecular Lines in Sunspot Umbral Spectra

Bagare

Kumar²,

Rajamanickam³

2006

Sol Phys

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High resolution FTS sunspot umbral spectra from NSO/Kitt Peak were used to detect rotational lines due to 11 electronic transitions of the molecule AlF, in the wavelength region 4400 -9000Å. The presence of lines due to bands C -A (0,0), (0,1), (0,2) and (1,2), D -A (0,0) and (0,1), F -A (0,0), G -A (0,0), and F -B (0,0) is confirmed. Further, the presence of lines due to C -A (1,0) and (1,1) transitions is treated as doubtful because of heavy blending in the region, by rotational lines of TiO. Among the identified lines, those which are well resolved were selected for measurement of equivalent widths. The measured values for the bands D -A (0,0) and F -A (0,0) were used to estimate the respective effective rotational temperatures to be 1240 ± 120 K and 2390 ± 400 K.

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Franck–Condon factors and r-centroids for a number of band systems of the astrophysical molecule AlF

Cited by 8 publications

References 14 publications

Theoretical study on the transition properties of AlF

Theoretical study on the transition properties of AlF

Collision induced rotational excitation of AlF (X 1Σ+) by para-H2 (j=0)

Identification of AlF Molecular Lines in Sunspot Umbral Spectra

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