electronic structure theory

Question 1

wavefunction depends on coordiantes of all

Answer 1

electrons and all nuclei

Question 2

wlwctrons are very light compared to nuclie which means they

Answer 2

move much faster

Question 3

born-oppenheimer approximaiton

Answer 3

nuclei as fixed in space and electrons can then be viewed as moving within the fixed nuclear framework

Question 4

withon the born-oppenheimer approximation the nuclei can be regarded as moving on the

Answer 4

potenial energy surface

Question 5

nuclear wavefunction depends on ell the

Answer 5

nucleir and describes nuclear motion

Question 6

electronic wavefunction depends on all the

Answer 6

electrons and E_e is the elcetronic energu

Question 7

as nuclear coordinates vary the …. and … will change

Answer 7

electronic wavefunction and electronic energy

Question 8

total wavefunction is

Answer 8

nuclear wavefunciton times electronic wavefunction

Question 9

spin orbital is a combination of

Answer 9

spatial orbitals and spin functions

Question 10

spin orbital tells us the

Answer 10

postion and spin of an electron

Question 11

electronic wavefunction depends on the

Answer 11

space-spin coordinates of all electrons

Question 12

From the pauli principle it must be

Answer 12

antisymmetric with respect to exchange of electrons

Question 13

the electronic wavefunction must change sign if we interchange the

Answer 13

space-spin coordinates of any two electrons

Question 14

antisymmetric wavefunctions can be easily represented using

Answer 14

determinants

Question 15

restriced hartree-fock theory

Answer 15

approximating electronic wavefunction by a single slater determinant and restrict spatial orbitals occupied by alpha electrons to be the same as the spatial orbitals occupied by the beta electrons

Question 16

total electronic energy is the expectation value of the

Answer 16

lectronic hamiltonian

Question 17

V_nn is the

Answer 17

nuclear - nuclear repulsion energy

Question 18

exchange energy is an energy

Answer 18

lowering that arises from the Pauli requirment that the electronic wavefunction be antisymmetric

Question 19

2 electrons of like spin cannot be at the same point in space so there is a

Answer 19

reduction in electron repulsion and energy lowering is the exchange energy

Question 20

the exchange energy is an energy lowering (reduction in repulsion) that arises from the

Answer 20

Pauli requirement that the electronic wavefunction by antisymmetric

Question 21

exclusion principle 2 electrons of same spin

Answer 21

cannot be at same point in space

Question 22

like-spin electrons avoid one another which means there is a reduction in

Answer 22

electron repulsion

Question 23

variartion principle state the best orbitals are ones that

Answer 23

minimise energy

Question 24

sum of orbital energies does not equal the

Answer 24

total electronic energy

Question 25

the ionisation potential to remove an electron from orbital whilst leaving all other orbitals unchanged is the negative of the

Answer 25

ith Hartree-Fock orbital energy

Question 26

Kartree fock analysis ignores

Answer 26

relaxation of the orbitlas

Question 27

in reality orbital will adjust and the energy of the cation will

Answer 27

reduce

Question 28

The true Hart-ree - fock ionsiation potential tend to be too small due to

Answer 28

neglect of electron correlation