A Tale of Two Tails: Rotational Spectroscopy of -Ethyl Maleimide and -Ethyl Succinimide.

Broadband microwave spectra of -ethyl maleimide (NEM) and -ethyl succinimide (NES) have been recorded using chirped pulse Fourier transform microwave spectroscopy in the -band (26.5-40 GHz). The spectra for both molecules were fit to a Watson A-reduced Hamiltonian in the I representation to obtain best fit experimental rotational constants (NEM: = 2143.