Identification of CrH and CrD Molecular Lines in the Sunspot Umbral Spectrum

Viswanathan, Balakrishnan; Shanmugavel, R.; Bagare, S. P.; Rajamanickam, N.; Sriramachandran, P.

doi:10.1007/s11207-009-9374-1

Cited by 8 publications

(6 citation statements)

References 10 publications

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“…Engvold et al (1980) identified CrH in the spectra of sunspots using the lines of the A-X transition. The presence of CrH molecule in sunspot umbral spectra has been confirmed by Viswanathan et al (2009). Also CrH molecular bands have been identified in the spectra of very low mass stars, brown dwarfs and substellar objects (Basri 2000).…”

mentioning

confidence: 67%

“…The majority of these band lines are also severely blended with TiO molecular lines. These temperatures lead to an average value of effective rotational temperature of 2169 K. The effective temperature has been estimated for A 6 + -X 6 + (0, 0) bands with integer rotational quantum numbers of CrH molecule to be 1412 ± 29 K by Viswanathan et al (2009). The average temperature of the FeH molecule for the two P (J ) branches of the (7/2-7/2) sub band in the (0, 0) transition is 1740 ± 100 K reported by Mulchaey (1989) and the majority of the molecular lines are also severely blended with other molecular and atomic lines.…”

Section: Resultsmentioning

confidence: 99%

“…The total number of lines Table 4 Lines identified as present in the CrH A 6 + -X 6 + (1, 1) band in sunspot umbra identified in a given band was noted as the I-parameter of the corresponding band. The probability of chance coincidence between laboratory and sunspot umbral wavenumbers can be tested by means of Russell-Bowen formula (Viswanathan et al 2009 andSriramachandran et al 2009). In the method of Wavenumber coincidence, the procedure of identification is completed as the list of accurate wavenumbers for a particular transition band of the selected molecule and the sunspot umbral spectrum are compared for coincidences.…”

Section: Crh Solar Identificationmentioning

confidence: 99%

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On the effective temperature of large sunspot umbra using CrH sextets electronic state molecular lines

Sriramachandran¹,

Shanmugavel²

2011

Astrophys Space Sci

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A high-resolution spectrum clearly shows the presence of A 6 + -X 6 + (0, 0; 0, 1; 1, 0; 2, 0; 2, 1) and (2, 2) bands system of CrH molecular lines in the spectral range 10,000 cm −1 to 14,050 cm −1 . At least 3928 lines of the six bands, accounting for 57% of the lines registered in the laboratory can be identified with certainty in the sunspot spectrum. Most of the lines are found blended with TiO, CaH, MgH and other atomic species. These molecular lines are typically much more temperature sensitive than atomic lines, which make them ideal, complementary tool for studying cool stellar atmospheres as well as the internal structure of sunspots. Equivalent width for an adequate number of well identified molecular lines of these bands using the Gaussian-profile approximation method versus rotational quantum number J has been used to determine the effective rotational temperature of the CrH molecule. The range of effective rotational temperature value obtained from these bands is 1766 K to 2442 K. This range agrees well with the effective rotational temperatures derived for other molecules in sunspot umbrae.

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confidence: 67%

Section: Resultsmentioning

confidence: 99%

Section: Crh Solar Identificationmentioning

confidence: 99%

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On the effective temperature of large sunspot umbra using CrH sextets electronic state molecular lines

Sriramachandran¹,

Shanmugavel²

2011

Astrophys Space Sci

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“…Chromium hydride has been observed for many years in the photospheres of S-type stars and sunspots via the electronic transition A 6 Σ + −X 6 Σ + , measured in absorption (Lindgren & Olofsson 1980;Viswanathan et al 2009). The molecule in fact has been found to be an excellent indicator of L-type brown dwarfs (Kirkpatrick et al 1999a(Kirkpatrick et al , 1999bBurrows et al 2002).…”

Section: Introductionmentioning

confidence: 99%

TERAHERTZ SPECTROSCOPY OF CrH (X ⁶Σ⁺) AND AlH (X ¹Σ⁺)

Halfen

Ziurys

2016

ApJ

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New laboratory measurements of hydrides have been carried out using terahertz direct absorption spectroscopy. Spin components of the = ¬ N 2 1 transition of the free radical CrH (X 6 Σ + ) have been recorded in the range 730-734 GHz, as well as a new measurement of the = ¬ J 2 1line of AlH (X 1 Σ + ) near 755 GHz. Both species were created in an AC discharge of H 2 , argon, and metal vapor. For CrH, the chromium source was Cr(CO) 6 , while AlH was produced from Al(CH 3 ) 3 . The = ¬ J 4.5 3.5 and ¬ 3.5 2.5 fine-structure components were recorded for CrH, each which consists of resolved proton hyperfine doublets. For AlH, the two main quadrupole components, = ¬ F 4.5 3.5 and ¬ 3.5 2.5, of the = ¬ J 2 1transition were observed as blended features. These data were analyzed with previous ¬ 1 0 millimeter/submillimeter measurements with 6 Σ and 1 Σ Hamiltonians for chromium and aluminum hydrides, respectively, and rotational, fine-structure (CrH only), and hyperfine constants were derived. The new measurements have resulted in refined spectroscopic parameters for both species, as well as direct measurement of the respective ¬ 2 1 rotational transitions. This work also resolves a 10 MHz discrepancy in the frequency of the AlH line. CrH and AlH have already been observed in the photospheres of stars via their electronic transitions. These data will facilitate their discovery at submillimeter/terahertz wavelengths in circumstellar envelopes and perhaps in diffuse clouds.

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“…Viswanathan et al [11] have identified the CrH and CrD molecular lines in sunspot umbral spectrum. Pavlenko et al [12] have reported equilibrium studies of MgH, MgD, CrH and CrD molecules.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic Evaluation of Thermodynamic Parameters for Aluminum Based Diatomic Gas Molecules

Sriramachandran¹

2014

Int. J. Thermo

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On account of the high accuracy with which spectroscopic data are obtained, thermodynamic parameters estimated from these data are more reliable than those obtained by direct thermal measurements. Spectroscopic data of aluminum based diatomic gas molecules (AlO, AlH, AlD, AlF, AlC) and partition function theory have been used to evaluate the thermodynamical parameters in the temperature range 100 -3000 0 K. Equilibrium constants for astrophysically important chemical process have been calculated using partition function theory. It is noticed that for AlC the heat capacity decreases exponentially after the critical temperature 1200 0 K.

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Identification of CrH and CrD Molecular Lines in the Sunspot Umbral Spectrum

Cited by 8 publications

References 10 publications

On the effective temperature of large sunspot umbra using CrH sextets electronic state molecular lines

On the effective temperature of large sunspot umbra using CrH sextets electronic state molecular lines

TERAHERTZ SPECTROSCOPY OF CrH (X ⁶Σ⁺) AND AlH (X ¹Σ⁺)

Spectroscopic Evaluation of Thermodynamic Parameters for Aluminum Based Diatomic Gas Molecules

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Identification of CrH and CrD Molecular Lines in the Sunspot Umbral Spectrum

Cited by 8 publications

References 10 publications

On the effective temperature of large sunspot umbra using CrH sextets electronic state molecular lines

On the effective temperature of large sunspot umbra using CrH sextets electronic state molecular lines

TERAHERTZ SPECTROSCOPY OF CrH (X 6Σ+) AND AlH (X 1Σ+)

Spectroscopic Evaluation of Thermodynamic Parameters for Aluminum Based Diatomic Gas Molecules

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TERAHERTZ SPECTROSCOPY OF CrH (X ⁶Σ⁺) AND AlH (X ¹Σ⁺)