Homolytic dissociation of singlet lithium dimer


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Forum Vet
Kmh603
You can easily get your desired open-shell singlet solution by using the DFT module (and choosing
HF exchange), by selecting a multiplicity of -2 for the second lithium atom.
The input below shows all the needed steps.
start li2

geometry lidimer noautosym units angstrom
    Li                        8.00     0.00    0.00
    Li                        0.00     0.00    0.00
END

geometry li1 noautosym units angstrom
    Li                        8.00     0.00    0.00
END

geometry li2 noautosym units angstrom
    Li                        0.00     0.00    0.00
END

BASIS spherical
 Li   library  def2-qzvpp
end

SET geometry li1

dft
 xc hfexch
 mult 2
 ADAPT OFF
 SYM OFF
 VECTORS INPUT atomic OUTPUT li1.movecs
END
TASK dft

SET geometry li2
dft
 mult -2
 VECTORS INPUT atomic OUTPUT li2.movecs
END
TASK dft

SET geometry lidimer
dft
 odft
 mult 1
 VECTORS INPUT fragment li1.movecs li2.movecs OUTPUT lidimer.movecs
 mulliken
END
task dft