1. Sergiy Krasnokutski, Changhua Zhang and Dong-Sheng Yang University of Kentucky, Lexington, KY 40506, USA $ National Science Foundation $

2. TOF of Sc x O y clusters Common TOF in metal-ligand complex studies

3. Time of flight of the ions could be measured and related to their mass, and therefore a mass-selective spectrum could be obtained – hence the name mass-analysed threshold ionization (MATI). Advantages of MATI compare with ZEKE Disadvantages of MATI compare with ZEKE Background electrons are very rapidly dispersed in the ZEKE experiment by very small discrimination fields, the ions move more slowly and remain in the excitation region for much longer. MATI spectra have generally been of lower resolution than ZEKE spectra.

5. CAN2 = +2500 V CAN1 = +1700 V 320 V/cm -1 Laser pulse 2-5  s Time 1

6.  =3.6*F 1/2  = 2 *F 1/2  = 5 *F 1/2 1

7. CAN2 = +2500 V CAN1 = +1700 V 320 V/cm -1 Laser pulse 2-5  s Time 12

8. 2

9. Ionization laser frequency 45450 cm -1

11. 422 cm -1 714 cm -1 2 A g  1 A g 2 A g  3 B 1U

12. Ionization laser frequency 37600 cm -1

13.  E (cm -1 ) 0 15392 21255

14. Experiment, He Experiment, Ar Simulation, 300K Simulation, 100K 1 A 1  2 A 1

15. 440 668 274 204 300 754

16. The method to study cluster formation was developed This method was applied to study growth of scandium oxide clusters The Sc 2 O 2 is the main building block for the larger clusters