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1- A [blank_start]torque[blank_end] or [blank_start]moment[blank_end] is the tendency of a force to
rotate an object about an axis; (units: [blank_start]newton.m[blank_end])- Atorque
- Bmoment
- Cnewton.m
2[blank_start]Angular momentum (L)[blank_end] is a rotational analog of linear momentum.
which equals [blank_start]r x linear momentum(p)[blank_end]- AAngular momentum (L)
- Br x linear momentum(p)
3[blank_start]Hamiltonian[blank_end] of
the system ([blank_start]H[blank_end]); it is a wave mechanical description of the kinetic
energy plus the potential energy- AHamiltonian
- BH
4The wave function ψ describes how the system behaves as [blank_start]waves[blank_end];
- Awaves
5shapes and energies of
the wave functions that describe the [blank_start]distribution of electrons[blank_end] in
atoms and molecules.- Adistribution of electrons
6- σ and σ* molecular orbitals (MOs) are formed from a
combination of two [blank_start]s[blank_end]-type
- π and π* MOs are formed from two [blank_start]p[blank_end]-type AOs.- As
- Bp
7most organic molecules, only the π − π* and n–
π* transitions lie within the [blank_start]200[blank_end]–[blank_start]800[blank_end] nm range of the UV/visible
spectrum.- A200
- B800
8y favored electron promotion will generally
be from the [blank_start]highest[blank_end] occupied molecular orbital (HOMO, e.g. π
and n) to the [blank_start]lowest[blank_end] unoccupied molecular orbital (LUMO; e.g.
π*)- Ahighest
- Blowest
9two or more states of the molecule have the same numerical value
of energy, they are said to be [blank_start]degenerate[blank_end].- Adegenerate
10In some cases, degeneracy can be removed by an [blank_start]external[blank_end]
influence, such as an [blank_start]electric[blank_end] or [blank_start]magnetic[blank_end] field, thus leading to
“split” energy levels- Aexternal
- Belectric
- Cmagnetic
11magnetic moment is much [blank_start]smaller[blank_end] than that of the electron
- Asmaller
12all the [blank_start]even[blank_end] A nuclides
have spin I=0 since there are even numbers of both neutrons and protons.- Aeven
13electric wave are usually [blank_start]dominant[blank_end]
- Adominant
14Plane-polarized light can be considered to arise from a source that
only oscillates [blank_start]parallel[blank_end] to one axis- Aparallel
15inclusion of neutrons and electrons in Figure is not strictly
correct, as these are particles with [blank_start]finite[blank_end] rest mass (m) while
electromagnetic radiation has [blank_start]zero[blank_end] rest mass.- Afinite
- Bzero
16Thermal motion leads to the distribution of molecules among the
energy levels available to them.
Higher energy states are exponentially [blank_start]less[blank_end] likely to be populated
than lower energy ones.
The exact distribution depends on the [blank_start]temperature[blank_end] and the
[blank_start]separation between energy levels (ΔE) ([blank_end]Figure).- Aless
- Btemperature
- Cseparation between energy levels (ΔE) (
17The charge displacement that occurs during a transition
between energy levels can be of two kinds:
1.A [blank_start]linear[blank_end] displacement—this corresponds to an [blank_start]electric[blank_end]
transition dipole and is written as μe
. (A dipole arises when there
is a separation of charge).
2. A [blank_start]rotation[blank_end] of charge—this corresponds to a [blank_start]magnetic transitiondipol[blank_end]e, μm . (A charge rotation generates a magnetic moment
[blank_start]perpendicular[blank_end] to the rotation- Alinear
- Belectric
- Crotation
- Dmagnetic transitiondipol
- Eperpendicular
18Dipoles, dipole moments, and their interactions are very
important for explaining many properties of molecules,
including [blank_start]non-covalent interactions[blank_end] and [blank_start]spectra[blank_end]- Aspectra
- Bnon-covalent interactions
19magnitude of the dipole moment [blank_start]μe[blank_end]
is [blank_start]qa[blank_end] which in SI
units is [blank_start]coulomb meter (C m)[blank_end] but the Debye (D = [blank_start]3.335 ×10−30[blank_end] C m)- Aμe
- Bqa
- Ccoulomb meter (C m)
- D3.335 ×10−30
20- A single point charge, q, generates a field, E, that falls of as [blank_start]1/r2[blank_end]
- For a dipole, μe
, the field E at P is the sum of the fields from +q and –
q and this falls off as [blank_start]1/r3[blank_end]
(the positive and negative charges of the
dipole tend to cancel at large distances so the field falls more
rapidly)- A1/r2
- B1/r3
21The transition dipole moment associated with a transition
between a [blank_start]ground[blank_end] state, g, and an [blank_start]excited[blank_end] state, e; is defined as
[blank_start]μge[blank_end]; this can have both μe and μm comp- Aμge
- Bground
- Cexcited
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- Quiz on Untitled, created by Manar Sherbeny on 21/11/2021.
- Author
- Manar Sherbeny
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- English
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