The Microwave Spectrum of the Methanol Dimer forK= 0 and 1 States

Rotational Spectra of Argon Acetone: A Two-Top Internally Rotating Complex

“…The selection rules are such that rotational transitions occur within the torsional substates causing a frequency splitting of a transition into 3 (AE and E A not resolved), 4, or 5 (E E split) transitions. An alternative labeling scheme used by some authors is A A = A, AE = E + , E A = E − , and E E = G (17,18).…”

Global Analysis ofa-,b-, andc-Type Transitions Involving Tunneling Components ofK= 0 and 1 States of the Methanol Dimer

“…The positions of c-type transitions for A 1 , A 2 , A 3 , A 4 states, which were not located experimentally in our earlier studies (4), cannot be predicted from the present formalism without prior knowledge of at least one tunneling frequency associated with exchange of the nonbonded lone pair and the hydrogen-bonded lone pair on the acceptor oxygen atom. (Such exchange occurs for tunneling motions represented by 1 3 n ϭ odd Ն 19 in Table 1 value of the lone-pair exchange tunneling splitting plus a contribution from the K-type doubling.…”

“…(4) and a guess that the lone-pair exchange tunneling frequency should be less than a few GHz, various candidates for c-type transitions in A i states were identified in our survey spectra. Some of these were then confirmed by zero-sum combination-difference loops, after careful remeasurement with the NIST Fourier transform microwave spectrometer (2,4).…”

“…(1)(2)(3)(4). Although we attempt to explain the larger changes in our thinking, it does not seem worthwhile to describe each of the smaller steps.…”

Application of Permutation–Inversion Group Theory to the Interpretation of the Microwave Absorption Spectrum of Dimethyl Methylphosphonate

“…[6], and D J K ,K (χ p , θ p , φ p ) is related to the direction cosine matrix in Eq. [5] used to rotate the intermediate axis system to the I r principal axis system of framework 1 with x = b, y = c, and z = a. (ii) If we assume that the directions of the intermediate x , y , z axes are not too different from the directions of the principal axes of the equilibrium configuration of framework 1, then D J K ,K (χ p , θ p , φ p ) takes one of six rather simple forms, corresponding to the rotations which take (x , y , z ) into (x, y, z), (z, −y, x), (y, z, x), (x, −z, y), (z, x, y), or (y, −x, z), respectively.…”