The collision induced deactivation constants of PH2 (X-2 B-1; v(2)" = 1) by H2S and NH3 have been determined. The NH3 constant appears to be anomalously high with respect to other polyatomic quenchers data in V-V energy transfer with PH2(v(2)" = 1). This deviation of the NH3 value has been ascribed to the inversion doubling of this molecule. The deactivation constant by PH3, determined in a previous work, has been re-examined. The removal of PH2(v(2)" = 1) should be due to two PH3 vibrational modes, i.e., v(2) and v(4), and not to the single v(4), as formerly assumed, and their respective contributions have been estimated. (c) 2005 Elsevier B.V. All rights reserved.