Chapter 1: Application of Mössbauer Spectroscopy to Energy Materials<br>Chapter 2: Mössbauer Spectral Studies of Iron Phosphate Containing Minerals and Compounds<br>Chapter 3: Mössbauer spectroscopic investigation of Fe-based silicides<br>Chapter 4: Mössbauer spectroscopy of catalysts<br>Chapter 5: Application of Mössbauer spectroscopy in studying catalysts for CO oxidation and preferential oxidation of CO in H2<br>Chapter 6: Application of 57Fe Mössbauer spectroscopy in studying Fe-N-C catalysts for oxygen reduction reaction in polymer electrolyte membrane fuel cells<br>Chapter 7: 197Au Mössbauer Spectroscopy of Thiolate-protected Gold Clusters<br>Chapter 8: Au Mössbauer spectroscopy of gold mixed-valence complexes, Cs2[AuIX2][AuIIIY4](X, Y = Cl, Br, I) and [NH3(CH2)nNH3]2[(AuII2)(AuIIII4) (I3)2] (n = 7, 8)<br>Chapter 9: Temperature- and photo-induced spin-crossover in molecule-based magnets<br>Chapter 10:Developing a Methodology to obtain new Photoswitchable Fe(II) Spin Crossover Complexes <br>Chapter 11:57Fe Mössbauer spectroscopy as a prime tool to explore a new family of colorimetric sensors<br> <br>