Planck,'s quantum hypothesis Planck formula(1900) 2hc25 hc/nk Max planck Completely fit the data Nobel 1918) Planck's constant: h=6.626x10-34. S The energy of any molecular vibration could be only some whole number multiply of hf.Planck’s quantum hypothesis 5 Planck’ formula (1900): Max Planck (Nobel 1918) 2 5 / 2 ( , ) 1 hc kT hc I T e        Completely fit the data! 34 h 6.626 10 J s  Planck’s constant:    The energy of any molecular vibration could be only some whole number multiply of hf