Knowledge Bank

The absolute intensities of all the J-multiplets between R(13) at 1375 $cm-1$ and P(12) at 1225 $cm-1$ in the $\nu 4$-fundamental of $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}CH4$ have been measured at $300\circ K$ . Our values are consistent with all the published band intensity measurements and the theoretical line strength computations of Fox. Spectral transmission computation using Lorentz line shape with a hydrogen-broadened half-width of $0.075cm-1$ $atm-1$ at $300\circ K$ for all the lines in the band is in excellent agreement with our data measured with a spectral resolution of $0.2cm-1$. Our best estimate for the absolute intensity of the band is $145\pm 8$ $cm^{-2}atm^{-1} $at S.T.P.