By observing the near-infrared spectrum of the quasar PG 1116+215 at z = 0.176 and combining with the HST/FOS spectrum, we obtained the relative strengths of three permitted OI lines ({lambda}1304, {lambda}8446, and {lambda}11287) in a quasar for the first time. The photon flux ratios of the OI lines of the quasar were compared with those previously measured in a Seyfert 1 and six narrow-line Seyfert 1s. No significant differences were found in the OI line flux ratios between the quasar and the other Seyferts, suggesting that the gas density in the OI and FeII line-emitting regions in the quasar is of the same order as those in low-luminosity AGNs. It was also found that the line width of OI {lambda}11287 is significantly narrower than that of Ly{alpha}, which is consistent with OI and FeII emission occurring in the partly ionized regions at the outermost portion of the broad-line region where velocities are small.
Download