Hunt RH, Shelton WN, Flaherty FA, Cook WB
Department of Physics, The Florida State University, Tallahassee, Florida, 32306
J Mol Spectrosc. 1998 Dec;192(2):277-293. doi: 10.1006/jmsp.1998.7689.
The absorption spectrum of methanol vapor has been recorded at room temperature from 3200 to 4200 cm-1 with a 1.24-M path-difference Fourier transform spectrometer. Over 10 000 transitions to the torsion-rotation states n, tau J, K of the OH stretching fundamental band nu1 have been assigned, thereby greatly expanding the results of previous investigations. Approximately 4000 of the cleaner lines have been used to determine 665 excited state torsion-rotation levels with principal torsional quantum number n = 0 as well as 494 levels with n = 1, 286 levels with n = 2, and 14 levels with n = 3. These levels correspond to 86 values of the quantum numbers n, tau, K. Most of the levels of a given n, tau, K are perturbed resulting in irregular P-, Q-, and R-branch series. The J = 0 origins for 64 values of n, tau, K have been fitted and a value of 410 cm-1 obtained for the hindering potential barrier. This is in agreement with a previous study of grating spectra but is lower than that obtained in more recent analyses of n = 0 <-- 0 transitions observed for K </= 3 in very low temperature spectra. The criteria used here to select states to be fitted and the difficulties in estimating the J = 0 origins because of the many perturbing level crossings are discussed. Copyright 1998 Academic Press.
利用一台光程差为1.24米的傅里叶变换光谱仪，在室温下记录了甲醇蒸汽在3200至4200厘米⁻¹范围内的吸收光谱。已确定了超过10000个跃迁至OH伸缩基频带ν₁的扭转-转动状态n、τ、J、K，从而极大地扩展了先前研究的结果。大约4000条较清晰的谱线被用于确定主扭转量子数n = 0的665个激发态扭转-转动能级，以及n = 1的494个能级、n = 2的286个能级和n = 3的14个能级。这些能级对应于量子数n、τ、K的86个值。给定n、τ、K的大多数能级受到微扰，导致P、Q和R支系列不规则。对n、τ、K的64个值的J = 0起始点进行了拟合，得到阻碍势垒的值为410厘米⁻¹。这与先前对光栅光谱的研究一致，但低于在最近对极低温光谱中K≤3时观察到的n = 0←0跃迁分析中获得的值。讨论了此处用于选择要拟合的状态的标准以及由于许多微扰能级交叉而在估计J = 0起始点时遇到的困难。版权所有1998年学术出版社。
