Spontaneous desorption and phase transitions of self-assembled alkanethiol and alicyclic thiol monolayers chemisorbed on Au(1Â 1Â 1) in ultrahigh vacuum at room temperature

► Organic thiols chemisorbed on gold surface are desorbed spontaneously in UHV at RT. ► HT SAMs underwent phase transitions from c(4 × 2) phase to 4 × √3 phase. ► CHT SAMs underwent phase transitions from (5 × 2√3)R35° phase to disordered phase. ► Structural stability of SAMs in UHV strongly depends on van der Waals interactions.