No abstract

Itimc e o ulC rdeln for I,~nes gofi of inionmatiof is c"tomatt toa .,.qoie , hour owt rueam.. auecatmnq UI1w t t lhwrswumq unuaa,. Iat w esetauis ates ~Cin. The temperature variation of the elementary excitation spectrum of thin liquid 4 He films is derived within the ring diagram approximation. This theory is microscopic only in the long wavelength limit. Using this anomalous spectrum, the specific heat data adsorbed on Grafoil graphite and the first, second and third sounds are analyzed. The temperature variation of the phonon spectrum is very negligible for low temperatures. However, with increasing temperature from 0.6 ~ 0.7 K to near the vicinity of the two-dimensional transition temperature of 1.21 K, the temperature effect is significant regarding the physical properties of thin liquid 4He films. The temperature variation of the elementary excitation spectrum of thin liquid 4He films is derived within the ring diagram approximation. This theory is microscopic only in the long wavelength limit. Using this anomalous spectrum, the specific heat data adsorbed on Grafoil graphite and the first, second and third sounds are analyzed. The temperature variation of the phonon spectrum is very negligible for low temperatures. However, with increasing temperature from 0.6 -0.7 K to near the vicinity of the two-dimensional transition temperature of 1.21 K, the temperature effect is significant regarding the physical properties of thin liquid 4He films.