The Internal Rotation Potential Energy Coefficients for CH2DNH2 and CH2DCHO

✍ Scribed by C.Richard Quade; Chun Fu Su

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 39 KB
• Volume: 210
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.2001.8471

✦ Synopsis

Over the past decade, we have been determining the internal rotation potential energy coefficients for molecules with partially deuterated methyl groups such as CH 2 DOH (1a, 1c), CHD 2 OH (1a, 1c), CH 2 DOD (1b, 1c), CHD 2 OD (1a, 1c), CH 2 DSH (2), and CHD 2 SH (2). All of these molecules have asymmetric internal rotors with V 3 arising explicitly from the electronic motion in the molecules (3) and V 1 and V 2 arising primarily from the α-dependence of the zero-point energy of the other vibrations (4). We have also determined V 1 and V 2 for the -OH and -SH internal rotation in CH 3 CH 2 OH, CH 2 DCH 2 OH, CH 3 CD 2 OH, CH 3 CH 2 OD, CH 3 CD 2 OD (5a), CH 3 CH 2 SH, CH 2 DCH 2 SH, and CH 3 CH 2 SD (5b). However, for these molecules, V 1 and V 2 , like V 3 , are more dependent upon the electronic motion.

In this note, we report on the determination of V 1 and V 2 for CH 2 DNH 2 and CH 2 DCHO from torsional data of microwave rotational spectral analyses. In both cases we work with the K = 0 torsional energy differences rather than doing a full nonrigidity analysis. Our IAM program is not usable for these molecules.

CH 2 DNH 2 . Many years ago, Tamagake and Tsuboi (6) performed a microwave torsional-rotational spectral analysis for CH 2 DNH 2 . In the course of their analysis, they determined E(g -, g + ) = 3501.3 MHz

[1] E(t, g) = 7.060 cm -1