Nanyang Technological University

CHEM 3062

Lab questions
Lab1: Gaussian
Q1. Dihedral angle: angle between 2 planes formed between Y-C2 and X-C1
Q2. Unit for Gaussian = Hartees = !!
""## ! = 4.360 x 10-18J
h = reduced planck’s constant
Me = rest mass of electron
A0 = average electron nucleus distance of a hydrogen atom
Q3. Do we need to calculate electronic energy for H+ why?
A: electronic energy is defined as the movement of electrons from one point to another.
since the equation does not show electron moving (redox) don’t need to calculate.
Q4. What do you expect the geometry of H3O+ ion to be ?
A: trigonal pyramidal
Concepts:
- Dihedral angle
1. Angle between 2 places made form 3 atoms
- Internal energy = electric + vibrational + rotational + translational
- Rotation barrier = eclipsed conformation – staggered formation
- Conversion from hartees to KJ/mol
1. x 627.509kcal/mol x 4.184 kJ/kcal x 103 (just conversion factors)
2. X 4.3597 x 10-18 J x 6.022 x 1023 mol-1 (hartees to joules, then x by avogadros no.)
- Conversion from wavenumber (cm-1) to internal energy (Ev),
Wavenumber(cm-1)*speed of light = frequency (s-1)
- Energy of transition state – energy of reactants = Activation energy (Ea)