Comet C/1995 O1 (Hale-Bopp) emission lines

High-resolution and high signal-to-noise ratio spectra of Comet C/1995 O1 (Hale-Bopp), which provided continuous wavelength coverage from 5500{AA} to 8500{AA} and partial coverage from 4000{AA} to 5500{AA}, were obtained with the Coude Echelle Spectrograph at Beijing Astronomical Observatory on March 26, 28 and April 22, 1997. In the spectra we found 532 emission features, among which 459 lines from H, O, Na, C_2_, C_3_, CN, CH, NH_2_ and H_2_O^+^ were identified.

The intensity of sodium emission lines at 5890 {AA} and 5896 {AA} on April 22 increased about 5 fold compared to that recorded on March 26 and 28. The intensity ratio I_{lambda}5577_/(I_{lambda}6300_+I_{lambda}6364_) of [O I] is consistent with the formation of excited O atoms from the photodissociation of H_2_O.