Raman spectra of liquid n-alkanes. III. Energy difference between t r a n s and g a u c h e n-butane

Abstract
The energy difference between the trans and gauche forms of liquid n‐butane has been determined from the temperature dependence of Raman band intensities. A value of 557±13 cal/mole was derived from the summed integrated intensities of six bands of each rotamer measured at nine temperatures between 0 and −127 °C. This value is considerably lower than those determined earlier from Raman spectra of the liquid and is in line with ΔE values for longer n‐alkanes in the liquid state. However, there is a large difference between the value reported here for liquid n‐butane and that reported for the gas (∼966 cal/mole).