Tentative estimation of vibrational frequencies for bicyclo (1.1.1) fentane with the aid of electron diffraction data

Mean amplitudes of vibration for bicycle (1.1.1) pentane were calculated from estimated force constants. which by several trials were modified as to give the best possible agreement with observed mean amplitudes from electron diffraction. The vibrational frequencies from the same calculations are not believed to have real significane because of the rough approximations involved. but they may be useful as an aid in a future assignment of observed frequencies.