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Title: Excited singlet electronic states of acetylene: cis and trans structures and energetics

Abstract

Molecular electronic structure theory has been used to predict the equilibrium geometries and energies of acetylene in its excited singlet electronic states. A double zeta plus polarization basis set of contracted Gaussian functions was used in conjunction with self-consistent field and large scale configuration interaction wave functions. The first excited singlet state of acetylene is the trans /sup 1/A/sub u/ state, in agreement with the experimental studies of King, Ingold, and Innes. This result is particularly interesting because the lowest triplet state of C/sub 2/H/sub 2/ is not the /sup 3/A/sub u/ state but rather the cis /sup 3/B/sub 2/ state. The predicted geometry of the A /sup 1/A/sub u/ state is r/sub e/(CC)=1.384 A, r/sub e/(CH)=1.096 A, theta/sub e/(HCC)=121.7 /sup 0/, in good agreement with available spectroscopic data. The predicted relative energies of the excited singlet states are 5.06 eV (/sup 1/A/sub u/), 5.54 eV (cis /sup 1/A/sub 2/), 6.87 eV (/sup 1/B/sub 2/), and 7.29 eV (/sup 1/B/sub u/). Thus the energetic ordering of the singlet states is A/sub u/

Authors:
; ;
Publication Date:
Research Org.:
Department of Chemistry and Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720
OSTI Identifier:
7026751
Resource Type:
Journal Article
Journal Name:
J. Chem. Phys.; (United States)
Additional Journal Information:
Journal Volume: 73:11
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ACETYLENE; ELECTRONIC STRUCTURE; EXCITED STATES; CONFIGURATION INTERACTION; GEOMETRY; ISOMERS; ALKYNES; ENERGY LEVELS; HYDROCARBONS; MATHEMATICS; ORGANIC COMPOUNDS; 640302* - Atomic, Molecular & Chemical Physics- Atomic & Molecular Properties & Theory

Citation Formats

So, S P, Wetmore, R W, and Schaefer, III, H F. Excited singlet electronic states of acetylene: cis and trans structures and energetics. United States: N. p., 1980. Web. doi:10.1063/1.440049.
So, S P, Wetmore, R W, & Schaefer, III, H F. Excited singlet electronic states of acetylene: cis and trans structures and energetics. United States. https://doi.org/10.1063/1.440049
So, S P, Wetmore, R W, and Schaefer, III, H F. 1980. "Excited singlet electronic states of acetylene: cis and trans structures and energetics". United States. https://doi.org/10.1063/1.440049.
@article{osti_7026751,
title = {Excited singlet electronic states of acetylene: cis and trans structures and energetics},
author = {So, S P and Wetmore, R W and Schaefer, III, H F},
abstractNote = {Molecular electronic structure theory has been used to predict the equilibrium geometries and energies of acetylene in its excited singlet electronic states. A double zeta plus polarization basis set of contracted Gaussian functions was used in conjunction with self-consistent field and large scale configuration interaction wave functions. The first excited singlet state of acetylene is the trans /sup 1/A/sub u/ state, in agreement with the experimental studies of King, Ingold, and Innes. This result is particularly interesting because the lowest triplet state of C/sub 2/H/sub 2/ is not the /sup 3/A/sub u/ state but rather the cis /sup 3/B/sub 2/ state. The predicted geometry of the A /sup 1/A/sub u/ state is r/sub e/(CC)=1.384 A, r/sub e/(CH)=1.096 A, theta/sub e/(HCC)=121.7 /sup 0/, in good agreement with available spectroscopic data. The predicted relative energies of the excited singlet states are 5.06 eV (/sup 1/A/sub u/), 5.54 eV (cis /sup 1/A/sub 2/), 6.87 eV (/sup 1/B/sub 2/), and 7.29 eV (/sup 1/B/sub u/). Thus the energetic ordering of the singlet states is A/sub u/},
doi = {10.1063/1.440049},
url = {https://www.osti.gov/biblio/7026751}, journal = {J. Chem. Phys.; (United States)},
number = ,
volume = 73:11,
place = {United States},
year = {Mon Dec 01 00:00:00 EST 1980},
month = {Mon Dec 01 00:00:00 EST 1980}
}