This book covers the introduction of common industrial conversion methods and researches on methane gas conversion. The first chapter simply describes the common industrial methods and also the importance of current research approaches of converting methane molecules into valuable hydrocarbons. The second chapter discusses the interaction of femtosecond lasers with multi-atomic molecules, ionization and dissociation processes, and finally selective bond dissociation by optimally strong pulsed lasers. Chapter 3 introduces some accurate computational methods for investigation of interaction between strong femtosecond laser pulses and molecules. Chapter 4 presents the molecular dynamics, dissociation process and the response of methane molecule to ultrafast intense laser pulses by reasonable different approaches.

*Elnaz Irani,Assistant Professor,"Tarbiat Modares University",Tehran,Iran; PhD:"Sharif University of Technology",Tehran, Iran;* Rasoul Sadighi-Bonabi, Professor,"Sharif University of Technology",Tehran,Iran; PhD:"UT Dallas",USA;* Abbas Anvari, Professor,"Sharif University of Technology",Tehran,Iran;PhD:"Chalmers University of Technology", Swedan.