Oscillations were observed across the whole solar disk using the Doppler shift and line depth of spectral lines from the CO molecule near 4666 nm with the National Solar Observatory ’ s McMath/Pierce solar telescope . Power , coherence , and phase spectra were examined , and diagnostic diagrams reveal power ridges at the solar global mode frequencies to show that these oscillations are solar p-modes . The phase was used to determine the height of formation of the CO lines by comparison with the IR continuum intensity phase shifts as measured in ( 9 ) ; we find the CO line formation height varies from 425 < z < 560 km as we move from disk center towards the solar limb 1.0 > \mu > 0.5 . The velocity power spectra show that while the sum of the background and p-mode power increases with height in the solar atmosphere as seen in previous work , the power in the p-modes only ( background subtracted ) decreases with height , consistent with evanescent waves . The CO line depth weakens in regions of stronger magnetic fields , as does the p-mode oscillation power . Across most of the solar surface the phase shift is larger than the expected value of 90 degrees for an adiabatic atmosphere . We fit the phase spectra at different disk positions with a simple atmospheric model to determine that the acoustic cutoff frequency is about 4.5 mHz with only small variations , but that the thermal relaxation frequency drops significantly from 2.7 to 0 mHz at these heights in the solar atmosphere .