Before doing a calculation, sketch how the overlap between a 1s orbital and a 2p orbital directed towards it can be expected to depend on their separation. The overlap integral between an H1s orbital and an H2p orbital directed towards it on nuclei separated by a distance R is S = (\(R / a_{0}\)){1 + (\(R / a_{0}\))+ \(\left.\frac{1}{3}\left(R / a_{0}\right)^{2}\right\} \mathrm{e}^{-R / a_{0}}\). Plot this function, and find the separation for which the overlap is a maximum.
Text Transcription:
R/a_0
13R/a_0^2e^-R/a_0
Intermolecular Forces - Molecules leave surface of liquids and enter gas state; re-enter liquid phase through surface - When vapor pressure = room pressure, the liquid is then boiling - Compounds are held together by different forces - Dipole- no + or -; distributed evenly - Hydrocarbons are always nonpolar - Van der Waal’s forces: attractive forces that hold particles together in the condensed phases that include dipole-dipole interactions and dispersion forces - Dispersion forces are present in all molecules to hold them together - Dipole attraction must include polar molecules - Hydrogen bonding occurs in molecules that contain H bonded to a small electronegative atom - Crystal structure of extended solids: Unit cell represents simplest structure - Simple cubic 1 unit cell=8 corner atoms * ⅛ = 1 total atom - Body- centered cubic 1 unit cell=8 corner atoms * ⅛ + atom in middle = 2 - Tungsten Volume Unit cell Unit cell Unit cell SC 1 atom/cell; BCC 2 atoms/cell; FCC 4 atoms/cell
