howto:rtp_field_xas
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howto:rtp_field_xas [2023/10/11 09:51] – [CP2K input] glebreton | howto:rtp_field_xas [2023/10/16 16:15] – oschuett | ||
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In this tutorial, we will present a simulation of resonant X-Ray excitation of an isolated carbon monoxide in real-time using a time-dependent field. | In this tutorial, we will present a simulation of resonant X-Ray excitation of an isolated carbon monoxide in real-time using a time-dependent field. | ||
On this page, you will find an overview of the method, some equations, and the CP2K input file. | On this page, you will find an overview of the method, some equations, and the CP2K input file. | ||
- | A longer version is available in the form of a jupyter notebook file in {{: | + | A longer version is available in the form of a jupyter notebook file in {{ : |
This kind of calculation is not easy to grasp: do not hesitate to have a first look before diving into the equations and details! | This kind of calculation is not easy to grasp: do not hesitate to have a first look before diving into the equations and details! | ||
This tutorial is connected to this article REF where you can find complementary information. | This tutorial is connected to this article REF where you can find complementary information. | ||
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All the time-dependent Molecular Orbitals are projected (TD_MO_INDEX = -1) and these projections are stored separately (SUM_ON_ALL_TD .FALSE.). This calculation is spin-independent so one does not have to define the spin of the MO to project. | All the time-dependent Molecular Orbitals are projected (TD_MO_INDEX = -1) and these projections are stored separately (SUM_ON_ALL_TD .FALSE.). This calculation is spin-independent so one does not have to define the spin of the MO to project. | ||
- | The reference to projected | + | The reference to projected |
- | There are $N_e/2 = 7$ molecular orbitals for carbon monoxide. There are thus 7 time dependent MOs (the $i$) and 7 reference MO (the $j$), so that there will be $7x7=49$ projection per time step: | + | There are $N_e/2 = 7$ molecular orbitals for carbon monoxide. There are thus 7 time-dependent MOs (the $i$s) and 7 reference MO (the $j$s), so that there will be $7x7=49$ projection per time step: |
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- | Now, let us focus on the second and third projections which can be viewed as excited-state projections: | + | Now, let us focus on the second and third projections which can be viewed as projections toward |
< | < | ||
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</ | </ | ||
- | In this case, all the time-dependent MO are involved in the projection and stored separately. This time, the reference wave function is supposed to be from an XAS_TDP calculation, | + | In this case, all the time-dependent MO are involved in the projection and stored separately. This time, the reference wave function is supposed to be from an XAS_TDP calculation, |
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Where $c_\omega^a$ is the $a^{\text{th}}$ atomic coefficient of the excited state found in the XAS_TDP module. | Where $c_\omega^a$ is the $a^{\text{th}}$ atomic coefficient of the excited state found in the XAS_TDP module. | ||
- | There will thus be 7 projections per time step in this case. The excited state population associated | + | There will be 7 projections per time step in this case: one for each time-dependent MO. The excited state population associated |
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- | The carbon monoxide molecule has a rotational symmetry along its CO bond: if one notes this axis $z$, then the $x$ and $y$-axis are equivalent by symmetry. It happens that the first available excited state for the Oxygen 1s is degenerate: there are two available states orthogonal in the $xy$-plane. | + | The carbon monoxide molecule has a rotational symmetry along its CO bond. If one notes this axis $z$, then the $x$ and $y$-axis are equivalent by symmetry. It happens that the first available excited state for the Oxygen 1s is degenerate: there are two available |
- | Therefore, the excited state should be understood as the some over these two frequency | + | Therefore, the excited state should be understood as the sum over the two equivalent |
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- | Where $\omega' | + | Where $\omega' |
howto/rtp_field_xas.txt · Last modified: 2024/02/24 10:02 by oschuett