Atomi polielettronici Flashcards

1
Q

What is the form of the Slater orbital used in the variational method for a helium atom?

A

The Slater orbital used in the variational method for a helium atom has the form ϕ(r) = √(ζ^3/πao) * e^(-ζr/ao), where ζ is a variational parameter and ao is the Bohr radius.

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2
Q

What is the effect of the electron-electron interaction on the monoelectronic energies in a helium atom?

A

The electron-electron interaction affects the monoelectronic energies in a helium atom by reducing the effective nuclear charge seen by each electron.

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3
Q

What is the energy expression obtained using the variational method for a helium atom?

A

The energy expression obtained using the variational method for a helium atom is E = (ζ^2 - 2Zζ + 5/8ζ) * e^2/ao, where ζ is the variational parameter and Z is the nuclear charge.

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4
Q

What is the purpose of the effective Hamiltonian in treating poly-electronic atoms?

A

The purpose of the effective Hamiltonian in treating poly-electronic atoms is to simplify the problem by treating each electron as if it were in an effective potential due to the electron-electron interaction.

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5
Q

What is a Slater determinant?

A

A Slater determinant is a determinant constructed from spin-orbitals that respects the indistinguishability and antisymmetry of electrons and gives the total wave function of a multi-electron system.

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6
Q

What is the difference between the first excited state and the second excited state of helium?

A

The first excited state has a spin of 1 and corresponds to a triplet state, while the second excited state has a spin of 0 and corresponds to a singlet state.

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7
Q

What is the difference between the first excited state and the ground state of helium in terms of electron configuration?

A

The first excited state has an electron in a 2s orbital, while the ground state has both electrons in 1s orbitals.stato fondamentale aveva
una parte orbitale simmetrica ed un parte di spin antisimmetrica (= carattere
totale antisimmetrico) le prime due funzioni dello stato eccitato invece hanno
una parte orbitale antisimmetrica ed una parte di spin simmetrica

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8
Q

What is the Eigenvalue of Sz for the last two excited states of helium?

A

The Eigenvalue of Sz for the last two excited states of helium is 0.

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9
Q

What is the autovalore of Sz for the first two excited states of helium?

A

The autovalore of Sz for the first two excited states of helium is 1 or -1, corresponding to a triplet state.

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10
Q

Quali sono i valori di Ms per i tre orbitali degeneri

A

1,-1 e 0

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11
Q

What is the Unsold theorem?

2 / 20

A

The Unsold theorem states that in a subshell with a complete set of electrons, the electron density is spherically symmetric, and the potential energy can be approximated as a central potential that depends only on the distance from the nucleus.

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12
Q

What is the effective Hamiltonian in the SCF method?

A

The effective Hamiltonian in the SCF method is the Hamiltonian that includes the electron-nucleus interaction and the average electron-electron repulsion. It is given by H_eff = -(h^2/2m)∇^2 + V_eff(r), where V_eff(r) is the effective potential energy that depends only on the distance r from the nucleus.

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13
Q

What is the purpose of the SCF method?

A

The purpose of the SCF method is to calculate the electronic structure of a many-electron system, such as an atom or a molecule, by solving the Schrödinger equation self-consistently.

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14
Q

What is the energy expression for the SCF method?

A

The total energy of the system in the SCF method is given by E = ∑(i=1 to n) εi - ∑(i=1 to n) ∑(j>i) Jij, where εi is the energy of the i-th electron and Jij is the Coulomb repulsion energy between the i-th and j-th electrons.

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15
Q

What is the Coulomb repulsion energy between two electrons?

A

The Coulomb repulsion energy between two electrons placed in different orbitals

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16
Q

What is the self-consistent field method?

A

The self-consistent field method is a method used in the Hartree method to achieve self-consistency by iterating the calculation of the potential and the wave functions until the eigenvalues no longer change.

17
Q

What is the self-consistent field method?

A

The self-consistent field method is a method used in the Hartree method to achieve self-consistency by iterating the calculation of the potential and the wave functions until the eigenvalues no longer change.

18
Q

What is the purpose of the Hartree method?

A

The purpose of the Hartree method is to solve the Schrödinger equation for a many-electron atom by treating each electron as if it moves in an average field created by all the other electrons.

19
Q

What is the center field approximation in the Hartree method?

A

The center field approximation in the Hartree method is when the potential is mediated on the angles so that it depends only on r.

20
Q

What is the starting defect in the Hartree approach?

A

The starting defect in the Hartree approach is that it completely overlooked spin.

21
Q

What is the operator of Fock?

A

The operator of Fock is an effective monoelectronic Hamiltonian containing kinetic energy, nucleus electron interaction, and potential effective due to all other electrons.

22
Q

What is the advantage of Roothan’s idea in the Hartree-Fock method?

A

The advantage of Roothan’s idea in the Hartree-Fock method is that it transforms the problem from the solution of integro-differential equations of Fock to the solution of a system of homogeneous linear equations.

23
Q

What is the formula for the system energy in the Hartree-Fock method?

A

The formula for the system energy in the Hartree-Fock method is E = 2∑i hi(1) + ∑ij (2Jij - Kij).

24
Q

What is the iterative treatment in the Hartree-Fock method?

A

he iterative treatment in the Hartree-Fock method involves choosing initial (orbital) functions, obtaining new orbitals with which to recalculate a new Fock operator and then new functions, etc., until the functions do not change further in two successive cycles.

25
Q

What is the third term in the formula for the system energy in the Hartree-Fock method?

A

The third term in the formula for the system energy in the Hartree-Fock method is the sum of the exchange supplements, which has no simple interpretation from a classical perspective.

26
Q

What is the significance of the vector model of the atom?

A

Explain how the vector model of the atom is useful for understanding the angular momentum total of a polyelectron atom.