2005MNRAS.356.1276O

Using the Near Infrared Spectrometer (NIRSPEC) spectrograph at Keck II, we have obtained infrared (IR) echelle spectra covering the range 1.5 -1.8 µm for the moderately reddened bulge globular clusters NGC 6342 and 6528, finding [Fe/H]=-0.60 and -0.17 dex, respectively. We measure an average α-enhancement of ~+0.33 dex in both clusters, consistent with previous measurements on other metal-rich bulge clusters, and favouring the scenario of a rapid bulge formation and chemical enrichment. We also measure very low ¹²C/¹³C isotopic ratios (~5 in NGC 6342 and ~8 in NGC 6528), suggesting that extra-mixing mechanisms resulting from cool bottom processing are at work during evolution along the red giant branch (RGB).