HOMO: Highest occupied molecular orbital.
Hydrodynamic radius: The radius of a sphere that diffuses at the same
rate as the molecule. Because most molecules are not spherical,
this radius is often smaller than the effective rotational radius.
Hydrogen bond: An especially strong dipole–dipole interaction between
hydrogen atoms bonded to an electronegative atom (e.g., O, N,
halogens) and another electronegative atom.
Hydrophobic effect: The entropically driven effect in which hydrophobic
molecules/components of molecules cluster together when in
water or another polar solvent such that the number of favorable
interactions between the polar solvent molecules is maximized.
Induced dipole: A dipole formed by the interactions of the electrons in a
molecule and an electric field, which may be from other molecules in the system or an external source (e.g., applied voltage).
Induced dipole interactions: Force existing between a permanent
dipole and a neighboring induced dipole.
Insulator: A material in which the energy difference between the highest
occupied quantum state in the valence band (or HOMO) and the
lowest unoccupied state in the conduction band (LUMO) is larger
than 3–4 eV. Insulators do not significantly conduct electricity or
absorb visible light.
Intensive property: A thermodynamic variable (e.g., temperature or
density) that does not depend on the amount of material present.
Interface: The two-dimensional region of space at which two different
phases contact each other.
Interferometry: The study of the ways in which light waves interact or
interfere with each other. Interferometric techniques use changes
in the interference of light waves with each other to determine
properties of a material.
Intermediate: A species that is both produced and consumed during the
course of a reaction.
Intermolecular force (F): Forces acting between sets of molecules, such
as hydrogen bonding or dipole−dipole interactions.
Intermolecular potential: A function that defines the potential energy of
a chemical system as a function of distance between components.
Glossary
445
Hydrodynamic radius: The radius of a sphere that diffuses at the same
rate as the molecule. Because most molecules are not spherical,
this radius is often smaller than the effective rotational radius.
Hydrogen bond: An especially strong dipole–dipole interaction between
hydrogen atoms bonded to an electronegative atom (e.g., O, N,
halogens) and another electronegative atom.
Hydrophobic effect: The entropically driven effect in which hydrophobic
molecules/components of molecules cluster together when in
water or another polar solvent such that the number of favorable
interactions between the polar solvent molecules is maximized.
Induced dipole: A dipole formed by the interactions of the electrons in a
molecule and an electric field, which may be from other molecules in the system or an external source (e.g., applied voltage).
Induced dipole interactions: Force existing between a permanent
dipole and a neighboring induced dipole.
Insulator: A material in which the energy difference between the highest
occupied quantum state in the valence band (or HOMO) and the
lowest unoccupied state in the conduction band (LUMO) is larger
than 3–4 eV. Insulators do not significantly conduct electricity or
absorb visible light.
Intensive property: A thermodynamic variable (e.g., temperature or
density) that does not depend on the amount of material present.
Interface: The two-dimensional region of space at which two different
phases contact each other.
Interferometry: The study of the ways in which light waves interact or
interfere with each other. Interferometric techniques use changes
in the interference of light waves with each other to determine
properties of a material.
Intermediate: A species that is both produced and consumed during the
course of a reaction.
Intermolecular force (F): Forces acting between sets of molecules, such
as hydrogen bonding or dipole−dipole interactions.
Intermolecular potential: A function that defines the potential energy of
a chemical system as a function of distance between components.
Glossary
445