14.00 o2 m simpson

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Research 2: M Simpson

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14.00 o2 m simpson

  1. 1. Lasers at the Interface of  Chemistry and Physics  Chemistry and Physics (Biology? Engineering?) Cather Simpson Department of Physics D t t f Ph i School of Chemical Sciences c.simpson@auckland.ac.nz p @ photonfactory.auckland.ac.nz
  2. 2. The Photon Factory Using short and ultrashort laser pulses ......to probe chemistry physics to chemistry, ... to machine on the μ to nanoscale
  3. 3. Important events happens on ultrashort time scales
  4. 4. Laser Interactions with Matter 35 fs pulses 100 fs pulses 10 ns pulses
  5. 5. Laser Micro‐ and Nanomachining "Research-grade" femtosecond system ⇒ 800 nm (tunable) ⇒ 100 fs (or 35 fs or ps scale) fs, ps-scale) ⇒ up to 3.5 mJ/pulse (λ dependent) ⇒ 6 μm feature size ⇒ 100 nm limit (Ag on glass λ/8) "Standard" nanosecond system ⇒ 248 nm; ~10 ns ⇒ up t 10 mJ/pulse to J/ l ⇒ 2 μm feature size ⇒ 300 nm limit feature size
  6. 6. Enabling Technology Basic, Targeted‐Basic and Applied Research Engender Technologies, Ltd.
  7. 7. 500 μm 1-3 μm
  8. 8. The Photon Factory James Tour  & coworkers P=P photochemistry – a new  twist on an old tale twist on an old taleThe Photon Factory ‐ Enabling Technology • robust, reliable source of pulsed laser light • pulses from nano‐ to femtoseconds • wavelengths from ultraviolet to infrared g f f • low to high pulse energies
  9. 9. New photoactive electronic materials Prof. John  Protasiewicz Transparent Protective Film P t ti Fil Dr. John Payton Light Emitting Polymer Film Dr. Brian Alberding Dr. Huo‐Lei Peng Dr. Nicole  Dickson Protective Film
  10. 10. Expanding the toolbox phospha-PPVs … polymer OLEDs photoactive polymers (photonics) solar energy harvesting? Prof. John  Protasiewicz PA P n PPV n n P PPE P n n
  11. 11. Photochemistry and the periodic table “… it is rather the heavy elements which behave normally and not the ll d t th more familiar elements of the first row” -- W. Kutzelnigg (1984) Angew. Chem. Int. Ed. Engl. 23:272-295
  12. 12. Photochemistry and Photophysics of Diphosphenes Mes Mes P P Mes M But But Prof. John Protasiewicz Mes But P P But j Prof. Masaaki Yoshifuji But But Dmp = 2,6-Mes2C6H3 Mes* = 2,4,6-tri-t-butylphenyl Urzenius E., Protasiewicz,J.D. (1996) Main Group Chem. 1:369. Yoshifuji, M. et al. (1981) JACS 103:4587.
  13. 13. Photochemistry and Photophysics of Diphosphenes What excited states are involved? What pathways between states are important? What structural features influence photobehaviour? P P Inversion P P 2 P P P Dissociative R R P P P P P P Rotation R R
  14. 14. Photochemistry and Photophysics of Diphosphenes What excited states are involved? What pathways between states are important? What structural features influence photobehaviour?Quantum chemistry calculations Density functional theory P CASPT2//CASSCF P Inversion P P 2 P P P ?? DissociativeUltrafast Spectroscopy R R fs-Transient Absorption P P impact of P - ligands P P P - excitation λ Rotation R R - solvent fs-Time resolved Raman
  15. 15. Ultrafast Transient Absorption & CASPT2//CASSCF
  16. 16. Ultrafast Transient Absorption & CASPT2//CASSCF π– π∗ 400 nm excitation ε ∼ 5 − 12,000 rbance S2 n+ – π∗ Absor ππ* (S2) singlet state ε ∼ 300 − 1500 τrise = 130 fs τ1 = 275 fs 300 350 400 450 250 500 τ2 = 20 ps Wavelength (nm) 480 nm excitation e citation S1 Mes n+π* (T1) triplet state P Mes P Mes τrise = 230 fs τ1 = 16 ps Mes τ2 = 200 ps DmpP=PDmp
  17. 17. Ultrafast Transient Absorption & CASPT2//CASSCF
  18. 18. The Photon Factory Using short and ultrashort laser pulses ......to probe chemistry physics to chemistry, ... to machine on the μ to nanoscale
  19. 19. Current Photon Factory Group Dr. Chuck Rohde (Physics) Sarah Th S h Thompson (Chemistry – PhD student) (Ch i t t d t) Julie Kho (Chemistry – PhD student) Christiaan Hougaard (BSc Hons Physics) S o s o Simon Ashforth (BTech Physics) ( ec ys cs) Past Members Sean Liew (BTech Physics) Laura Harvey (MSc Physics graduate) Edward Woon Wei An (BTech Physics) Kaidi Liang (BTech Physics) Jessica Hendy (BA Hons Anthropology) Ling Yan Pang (BTech Physics) James Park (BSc H J P k (BS Hons Ch i t ) Chemistry) Amy Lin (MSc. Physics) (MSc Josh Bradfield (Mechatronics Engineering) Emma Simpson (Physics exchange) Center for Fraser MacMillan (Engineering Science) Hafizah Rahim Chemical Dynamics Peter Hosking (Mechatronics Engineering) g( g g) Mona Xin Zhu (Biomedical Engineering) Current Collaborators Hayley Ware (Mechanical Engineering) Prof. David Williams Matthew Edmond (Engineering Science) Dr. Bryon Wright Isaac Hamling (Engineering Science) Dr. Dr Charles Unsworth Geran Zhang (Biomedical Engineering) Prof. Larry Chamley Prof. John Protasiewicz Prof. Terry Gustafson
  20. 20. Vice Chancellor’s Strategic Development Fund Chancellor sVice Chancellors MIRE ProgramFaculty of ScienceSchool of Chemical Science & Department of PhysicsAuckland UniServicesNational Science Foundation (USA) National (USA), Institutes of Health (USA), Department of Education (USA)

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