Table 4: Comparison between SFH (NR state assignment) and 4-component DCH of the spectroscopic constant. Above 𝑅 𝑒 (Å), middle 𝜔 𝑒 (cm−1), and below 𝐷 𝑒 (cm−1), calculated with PBE functional and aug-cc-pVTZ basis set. For 4-component states assignment gerade, ungerade follow the symmetry of state in the first line.

3 Π 𝑔 3 Σ + 𝑢 3 Π 𝑢 3 Σ + 𝑔

SFH2.3472.5344.7954.79
4-c. 0 𝑔 , 0 𝑢 2.3454.874
4-c. 0 + 𝑔 , 0 + 𝑢 2.3454.480
4-c. 0 𝑢 , 0 𝑔 2.5344.553
4-c. 1 𝑔 ( 1 𝑢 ) 2.3472.5344.6254.574
4-c. 2 𝑔 , 2 𝑢 2.3494.945

SFH219172727
4-c. 0 𝑔 , 0 𝑢 2206
4-c. 0 + 𝑔 , 0 + 𝑢 22013
4-c. 0 𝑢 , 0 𝑔 17233
4-c. 1 𝑔 ( 1 𝑢 ) 2191721334
4-c. 2 𝑔 , 2 𝑢 2198

SFH130971087052405
4-c. 0 𝑔 , 0 𝑢 1293452
4-c. 0 + 𝑔 , 0 + 𝑢 13130417
4-c. 0 𝑢 , 0 𝑔 10486533
4-c. 1 𝑔 ( 1 𝑢 ) 1290610680235550
4-c. 2 𝑔 , 2 𝑢 1306853