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### The orbital transition contribution in the electronic excitation process

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Registered: Jul 2019
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Dear all,

I had run a TDDFT calculation to obtain the vertical excitation energy in various solvents. I want to know how to get the contribution of orbital transition in the electronic excitation process. The following is part of the output file.
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TDDFT Excitation Energies
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Excited state 1: excitation energy (eV) = 2.8755
Total energy for state 1: -1459.39584292 au
Multiplicity: Singlet
Trans. Mom.: 4.2757 X 0.0000 Y 0.0000 Z
Strength : 1.2878838269
X: D( 90) --> V( 1) amplitude = 0.9999

Excited state 2: excitation energy (eV) = 3.3555
Total energy for state 2: -1459.37820286 au
Multiplicity: Singlet
Trans. Mom.: -0.0000 X -0.6336 Y 0.0130 Z
Strength : 0.0330167300
X: D( 89) --> V( 1) amplitude = 0.9852

Excited state 3: excitation energy (eV) = 4.2379
Total energy for state 3: -1459.34577460 au
Multiplicity: Singlet
Trans. Mom.: -0.9262 X -0.0005 Y -0.0000 Z
Strength : 0.0890610106
X: D( 8 --> V( 1) amplitude = 0.9531

Excited state 4: excitation energy (eV) = 4.3111
Total energy for state 4: -1459.34308416 au
Multiplicity: Singlet
Trans. Mom.: 0.0000 X 0.5184 Y -0.0047 Z
Strength : 0.0283839124
X: D( 87) --> V( 1) amplitude = 0.7704
X: D( 90) --> V( 2) amplitude = -0.5454

Excited state 5: excitation energy (eV) = 4.3964
Total energy for state 5: -1459.33994883 au
Multiplicity: Singlet
Trans. Mom.: -0.0000 X -0.2148 Y 0.0100 Z
Strength : 0.0049787277
X: D( 87) --> V( 1) amplitude = 0.5864
X: D( 90) --> V( 2) amplitude = 0.7645

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At first，I think the values of ”amplitude“ are on behalf of the orbital transition contribution of the electronic excitation. But, the total amplitudes of some excited states is not equal to 1. Could someone please answer my following questions? firstly，what does the amplitudes mean? Secondly，how to print the contribution of orbital transition in the electronic excitation process，like the CI coefficient in Gaussian software？

Best regards.

yingli