Inorganic Chemistry

Rotational Spectroscopy 1.  What is the degeneracy of the rotational energy level with  J  = 4 for a heteronuclear diatomic molecule? 2. The  A  rotational constant of a phosphorus pentafluoride, PF 5 , molecule is 3.566 Hz. Calculate the lengths of the equatorial P-F bonds. 3. The rotational constant of ICl is 0.1142 cm-1. Calculate the bond length of the molecule. 

Introduction to Spectroscopy; Part 3    Vibrational motion of a diatomic molecule can be considered as a simple oscillator. Therefore the hook’s law can be applied. (Equation 01) The frequency of a vibration is an important property of the vibrational transition. (Equation 02) Understanding the molecular vibration: Light (Energy) is absorbed when radiation frequency is equal to the frequency of vibration in a molecule. Covalent bonds vibration at only certain allowed frequencies and basically these vibrations include stretching and bonding.  For a vibrational spectrum; The dipole moment of the molecule must change during the vibration. Symmetric  stretching Anti Symmetric stretching Bending Degree of Freedom For a molecule with "N" atoms, total degree of freedom is given by 3N which include translation (3 df) rotaion ( linear 2 df / non linear 3df ) and vibration ( the rest; linear 3N- df/ nonlinea...

Introduction to spectroscopy: part 2 Rotational spectroscopy electromagnetic radiation lies in the microwave region ( λ = 30cm – 3mm) of the electromagnetic radiation spectrum. Rotational spectroscopy is applicable only for the molecules with a dipole moment. Samples are usually in gaseous state. Rigid diatomic molecules; A general equation can be derived using Schrödinger equation for a rigid rotor. Planck's constant = 6.626 × 10 -34 m 2 kg / s Normally Energy is given in the term of ṽ Selection Rules for a rigid rotor Needs a permanent dipole moment. only polar molecules can give a pure rotational spectrum. Only #1 type transitions can be used for rotational spectra. #2 can not be used. Spacing between Energy Levels The Energy gap between two energy levels is given by the equation which is derived below. The table 01: Rotational Energy levels Spectral lines: Moment of Iner...

Introduction to spectroscopy: part 1 The interaction between matter and radiation can be analyzed through spectroscopy. Radiation: basically radiation is energy transferred by electromagnetic waves . It includes x rays, gamma rays, visible light... etc. Properties of electromagnetic waves: v All electromagnetic waves travel at the same speed (C) v Wave length: (   λ ) the length of one complete cycle v Amplitude: (A) Half of the perpendicular height between a trough and a crest v Frequency: ( Hz ) The number of cycles per seconds v Wave number: (   ν ) The number of wavelengths that occupy per 1cm Wave Theory:      C = λ. V     Particle Theory: Quantum numbers: All energy levels are quantized. Because the energy levels are discrete, transition between energy states only occur when certain energy is absorbed. There are several transitions that can be investigated such as elect...