Considering the -CH3group as a single particle of 15.0 daltons, the infrared absorption intensities of the a1fundamentals vibrational bands of CH3NO2in CCl4have been measured at different concentrations considering two cases: band intensities with solvent substraction (wss) and without solvent substraction (wtss). In order to obtain the matrix of the normalized amplitudes, X, the vibrational problem was solved via compliance constant: KCX = XΦ, in this case the use of the minus sign of the ±(∂μ/∂Q1)2s expressions is justified. The experimental results of the intensities measurements were refined with a variance analysis. From the intensities experimental data, our results are: ∂μNO/∂rNO= 6.02 and 6.16 D/Å, μNO2= 1.29 and 1.34D and ∂NO/∂RNC= -2.62 and -2.68 D/Å for measurements without solvent substraction and with solvent substraction, respectively