MICROWAVE DETERMINATION OF THE STRUCTURE OF THE C(S) CONFORMATION OF DIPROPYL ETHER

Microwave spectroscopy of dipropyl ether has been performed by superso nic jet molecular beam electric resonance spectroscopy and by molecula r beam pulsed-jet Fourier transform spectroscopy. Calculations suggest that there are four distinct conformations of dipropyl ether that hav e energies within 0.5 kcal/mol of each other and have geometries of C2 v, C2, Cs, and C1 symmetry. The geometry of the C(s) conformation has been determined. The rotational constants of this conformation are A = 4793.6393(5) MHz, B = 1242.5098(3) MHz, C = 1053.3520(2) MHz, delta(J ) = 0.1 17(6) kHz, delta(K) = 1.25(5) kHz, DELTA(JK) = -2.807(7) kHz, DELTA(J) = 0.448(2) kHz, and DELTA(K) = 11.57(3) kHz. The outer torsio n angles (the O-C-C-C angles) are approximately 65-degrees. Unassigned transitions in the microwave spectrum suggest that more than one addi tional conformation is present in both CW and pulsed molecular jets.