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Molecular rydberg transitions. VIII. The geometry of ethylene in the R 1 s state
Author(s) -
Findley G. L.,
Wittel K.,
Felps W. S.,
McGlynn S. P.
Publication year - 2009
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560120828
Subject(s) - rydberg formula , atomic physics , vibronic coupling , rydberg state , spectral line , state (computer science) , chemistry , ethylene , potential energy , physics , absorption spectroscopy , coupling (piping) , quantum mechanics , materials science , ionization , excited state , ion , biochemistry , algorithm , computer science , metallurgy , catalysis
Abstract The vacuum ultraviolet absorption spectrum of 1,1‐C 2 H 2 D 2 has been reexamined. Using the symmetric top approximation and the Merer‐Schoonveld (A. J. Merer and L. Schoonveld, Can. J. Phys. 47 , 1731 (1969)) potential for the lowest‐energy s Rydberg ( R 1 s ) state of ethylene, the energies and relative intensities of the first few torsional vibrations ( v 4 ′) in the R 1 s state of 1,1‐C 2 H 2 D 2 have been computed. The agreement with experiment is excellent. This result negates the recent proposal (F. H. Watson, Jr. and M. N. Nycum, Spectrosc. Lett. 8 , 223 (1975)) that the N → R 1 s transition obtains allowedness only through vibronic coupling. The energies and relative intensities of v 4 ′ have also been computed for CH 3 D, 1,2‐C 2 H 2 D 2 ( cis and trans ) and C 2 HD 3 . The Merer‐Schoonveld potential is in excellent agreement with experiment in all instances. Some discussion of the photoelectron spectra is also provided.