In the present work, the selective preparation of C2H2 in discrete rotational states of the infrared inactive vibrational v mode in its electronic ground state (X1∑g+,v″2=1,J″= 9,11 and 13) is achieved by stimulated Raman excitation. From the UV laser induced fluorescence, A1Au(v′3=←X′∑g+ (v"2=1), the C2H2-C2H2 collisional R-R deactivation rate constants are measured. They are (7.96±1.04)×10-10cm3s-1 for J"= 9, (8.79±0.97)×l0-10cm3s-1 for J"= 11 and (8.76±0.88)×10-10cm3s-1 for J" = 13. The multiquanta R-R energy transfer rcte constants for trdnsitions from the initial pumped level to other different rotational states (v"2= 1, J" = 1,3,5,7,9,11,13,15) have been extracted directly.