Deactivation of the bending mode upsilon(2)＇ = 1 and upsilon(2)＇ = 0 vibrational levels of PH2((A) over tilde (2)A(1)), and of the upsilon(2)" = 1 level of ground state PH2((X) over tilde B-2(1)) due to collisions with the diatomic molecules H-2, N-2, CO, and NO has been investigated. The Parmenter and co-worker＇s, the Thayer and Yardley＇s, and the collision complex theories have been used to rationalize the PH2((A) over tilde( 2)A(1)) quenching data. Explanations for the deviations of the quenching data due to these molecular quenchers from the variation trend found, in a previous work, for the rare gas quenchers have been proposed. For the vibrational relaxation of PH2((X) over tilde B-2(1); 0, 1, 0), the data interpretation is based essentially on the theories by Schwartz, Slawsky, and Herzfeld-Tanczos, and Moore.