A Study of Absorption Features in the 3 Micron Spectra of Molecular Cloud Sources with H 2O Ice Bands

New 3.3-3.6 microns spectra were obtained of nine young stellar objects embedded in molecular clouds. An absorption feature at 3.47 microns (2880 cm -1) with FWHM 0.09 microns (80 cm -1), first identified by Allamandola et al. (1992), was definitively detected toward seven objects, and marginally in the other two. The feature is better correlated with H<SUB>2</SUB>O ice than with the silicate dust optical depth in the data obtained to date. Assuming the feature is due to a C-H stretch absorption, the abundance of the C-H bonds averaged along the lines of sight is closely related to that of H<SUB>2</SUB>O ice. We interpret the correlation with H<SUB>2</SUB>O ice as indicating that the C-H bonds form together with H<SUB>2</SUB>O ice on grain surfaces in the molecular clouds, though other formation mechanisms are not ruled out. A second absorption feature at 3.25 microns (3080 cm<SUP>1</SUP>) was detected toward NGC 7538/IRS 1 and S140/IRS 1; this feature was first detected in spectra of Mon R2/IRS 3 (Sellgren, Smith, &amp; Brooke 1994; Sellgren et al. 1995). There is as yet insufficient data t6 tell whether this feature is better correlated with H<SUB>2</SUB>O ice or silicates.