Absolute measurement of the S(0) and S(1) lines in the electric quadrupole fundamental band of D(2) around 3μm.
The electric quadrupole fundamental (v=1←0) band of molecular deuterium around 3 μm is accessed by cavity ring-down spectroscopy using a difference-frequency-generation source linked to the Cs-clock primary standard via an optical frequency comb synthesizer. An absolute determination of the line position and strength is reported for the first two transitions (J=2←0 and J=3←1) of the S branch. An accuracy of 6×10(-8) is achieved for the line-center frequencies, which improves by a factor 20 previous experimental results [A. R. W. McKellar and T. Oka, Can. J. Phys. 56, 1315 (1978)]. The line strength values, measured with 1% accuracy, are used to retrieve the quadrupole moment matrix elements which are found in good agreement with previous theoretical calculations [A. Birnbaum and J. D. Poll, J. Atmos. Sci. 26, 943 (1969); J. L. Hunt, J. D. Poll, and L. Wolniewicz, Can. J. Phys. 62, 1719 (1984)].
Istituto Nazionale di Ottica (INO)-Consiglio Nazionale Delle Ricerche (CNR), Comprensorio A. Olivetti, Via Campi Flegrei, Pozzuoli, Napoli 34-80078, Italy. pasquale.maddaloni@ino.it
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Maddaloni
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Malara
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De Tommasi
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De Rosa
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Ricciardi
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Gagliardi
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Tamassia
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Di Lonardo
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De Natale