I’m stuck on a Chemistry question and need an explanation. Quantum Chemistry Homework 4 questions, please ensure 80% accuracy before you bid the price. no plagiarism, no copy from online res
1) Write down the secular determinant for the π-bonding of the butadiene molecule (C_{4}H_{6}), ignoring overlap. [2 marks]
2) How many nodes are expected in each of the four π-molecular orbitals (_{1}, _{2},_{ 3}, _{4}) of butadiene? [2 marks]
3) The coefficients for the linear combination of atomic orbitals for the two lowest
energy π-MOs of butadiene are given below:
Normalised Coefficients | ||||
MO | Atom 1 | Atom 2 | Atom 3 | Atom 4 |
_{2} | +0.6015 | +0.3717 | –0.3717 | –0.6015 |
_{1} | +0.3717 | +0.6015 | +0.6015 | +0.3717 |
(i) Calculate the total π-electron density on atom 1. [2 marks]
(ii) Calculate the total π-electron density on atom 2. [2 marks]
(iii) Calculate the total π-bond order between atoms 1 and 2. [2 marks]
(iv) Calculate the total π-bond order between atoms 3 and 4. [2 marks]
(v) Predict the coefficients at each atom for the two highest energy π-MOs (_{3}, _{4}). [4 marks]
(vi) Present the MO diagram for butadiene, including sketches of each of the four MOs (_{1}, _{2}, _{3}, _{4}), clearly indicating the relative size and sign of the atomic orbital contributions at each atom. Justify the signs and sizings of the MOs. [4 marks]
4. (a) Use the simple one-electron molecular orbital method, including overlap, to calculate the energies of the molecular orbitals of the hydrogen molecule (H_{2}) in terms of α, β and S? [6 marks]
(b) Calculate given that = -13.6 eV, that S = 0.6, and that the lowest UV absorption
energy is 12 eV. [8 marks]
(c) Determine the ionisation energy of the bonding molecular orbital in H_{2 }? [6 marks]