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Excited‐state potential energy curves from time‐dependent density‐functional theory: A cross section of formaldehyde's 1 A 1 manifold
Author(s) -
Casida Mark E.,
Casida Kim C.,
Salahub Dennis R.
Publication year - 1998
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/(sici)1097-461x(1998)70:4/5<933::aid-qua39>3.0.co;2-z
Subject(s) - density functional theory , excited state , manifold (fluid mechanics) , rydberg formula , potential energy , chemistry , atomic physics , formaldehyde , planar , work (physics) , spectroscopy , molecular physics , computational chemistry , physics , quantum mechanics , ionization , mechanical engineering , organic chemistry , computer science , engineering , ion , computer graphics (images)
This work reports the first density‐functional theory (DFT) treatment of excited‐state potential energy surfaces exhibiting avoided crossings. Time‐dependent DFT (TD‐DFT) results, using a recently proposed asymptotically corrected local density approximation functional, are compared with multireference doubles configuration interaction (MRD‐CI) results for the 1 A 1 manifold of the CO stretching curves of planar formaldehyde. TD‐DFT is found to reproduce the qualitative features essential for understanding the spectroscopy of this manifold, specifically the strong mixing of the 1 (π, π*) with Rydberg transitions and the resultant avoided crossings. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 70: 933–941, 1998