Nascent vibrational distributions of NH2((X) over tilde (2) B-1, upsilon(2)" = 0-4) generated in the 193 nm photolysis of NH3 at 298 I K have been determined by simple kinetic analysis. The vibrational levels of NH2((X) over tilde B-2(1)) were detected by laser-induced fluorescence (LIF) excited via the (A) over tilde (2)A(1)-(X) over tilde B-2(1) system, and time-resolved concentration profiles were recorded. Rate constants for intramode relaxation of upsilon(2) vibration (upsilon(2)" --> upsilon(2)"- 1) by collisions of He have been determined to be (4.2 +/- 1.0) x 10x(-14), (7.5 +/- 0.5) x 10(-14), (1.6 +/-0.1) x 10(-13), (3.0 +/- 0.1) x 10(-13) in units of cml molecule(-1) s(-1) for upsilon(2)" = 1, 2, 3, and 4, respectively. The quoted errors are 2sigma. Rate constants for intermode coupling between upsilon(1)" 1 and upsilon(2)" = 2 by He have also been determined to be (4.7 1.6) x 10(-12) (upsilon(1)" =1 --> upsilon(2)" = 2) and (1.3 +/- 0.4) x 10(-12) cm(-3) molecule(-1) s(-1) (upsilon(1)" = 1 <-- upsilon(2)" = 2). Relative detectivities of the levels upsilon(2)" = 1-4 were obtained by the kinetic analysis, and vibrational distributions immediately after the photolysis have been given to be 2.2+/-0.7/1.0/ < 1.3/0.66 +/- 0.3/ < 3.0 for upsilon(2)" = 0/1/2/3/4 (normalized by the population of upsilon(2)" = 1). To the best of our knowledge, this is the first quantitative report on the initial vibrational populations of NH2 generated in the photolysis at 193 nm.