The normal mode analysis was executed for the ammonia-water cluster, (NH3)(3)(H2O)(9), i.e., a partial structure of the surface bound state via the density functional theory (DFT) calculation with the ammonia coverage of 0.33 ML on the (001) ice surface. In accordance with the recent infrared reflection absorption spectroscopy (IRAS) assignment, its characteristic vibrational bands were reproduced together with a new band prediction around 3248 cm(-1) originating from the N-H hydrogen bond vibration. The theoretical characterization reveals complementarily a clear evidence of the surface bound state that was experimentally found for the first time.