NEAR-INFRARED SPECTROSCOPY OF THE HIGH-REDSHIFT QUASAR S4-0636+68 AT Z = 3.2

We present near-infrared (observed frame) spectra of the high-redshift quasar S4 0636+68 at z = 3.2, which was previously thought to be one of a group of ''strong'' Fe II emitters [i.e., F(Fe II lambda lambda 4 434-4684)/F(H beta) > 1]. Our K-band spectrum clearly shows emission l ines of H beta and [O III] lambda lambda 4959, 5007, as well as optica l Fe II emission. Our computed value of F(Fe II lambda lambda 4434-468 4)/F(H beta) similar or equal to 0.8 for S4 0636+68 is less than previ ously thought and, in fact, is comparable to values found for radio-lo ud, flat-spectrum, low-z quasars. Therefore S4 0636+68 appears not to be a strong optical Fe II emitter. Although more than half (5/8) of th e high-z quasars observed to date are still classified as strong optic al Fe II emitters, their Fe II/H beta ratios, for the most part, follo w the same trend as do those of low-z quasars, i.e., an anticorrelatio n in EW(Fe II)/EW(H beta) versus EW([O III])/EW(H beta), with radio-lo ud quasars having a mean value of EW(Fe II)/EW(H beta) approximately h alf that of radio-quiet quasars at comparable values of EW([O III])/EW (H beta).