## Abstract

The line strength ratios of lines having a common upper rovibronic level but belonging to different P, Q, and R branches (rotational branching ratios) are, for the first time, measured for the diagonal (v′ = v″ = 0-3) bands of the I^{1}Π_{g}^{-} , J^{1}Δ_{g}^{-} → C^{1}Π_{u}^{±} electronic transitions of the D_{2} molecule. Within the framework of the nonadiabatic model, the ratio of the dipole moments of the 3d^{1}Δ_{g} → 2p^{1}Π_{u}and 3d^{1}Π_{g} → 2p^{1}Π_{u} electronic transitions. M_{2pπ}^{3dΔ}/M_{2pπ}^{3dπ}, was obtained from the previously calculated expansion coefficients in the Born- Oppenheimer basis set of perturbed wave functions of the I^{1}Π_{g}^{-} and J^{1}Δ_{g}^{-} states of the D_{2} molecule and experimental values of rotational branching ratios. It was found that, as in the case of H_{2}, there is a significant discrepancy between the values of M_{2pπ}^{3dΔ}/M_{2pπ}^{3dπ} derived from the analysis of experimental data on different electronic transitions: I^{1}Π_{g}^{-} → C^{1}Π_{u}^{±} and J^{1}Δ_{g}^{-} → C^{1}Π_{u}^{±}. The reasons for this discrepancy are discussed. At the same time, when the data on both molecules are considered on an equal footing, the effective value of M_{2pπ}^{3dΔ}/M_{2pπ}^{3dπ} = -1.42 ± 0.01, which agrees well with the value of -1.35 ± 0.05 that we obtained earlier for transitions between similar triplet states of H_{2} and D_{2} and is close to the estimate of - √2 in the pure precession approximation, corresponds to the whole body of the measured rotational branching ratios of the molecules H_{2} and D_{2}.

Original language | English |
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Pages (from-to) | 34-39 |

Number of pages | 6 |

Journal | Optics and Spectroscopy (English translation of Optika i Spektroskopiya) |

Volume | 80 |

Issue number | 1 |

State | Published - 1 Dec 1996 |

## Scopus subject areas

- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics