Identification of the  3 ( σ ) mode of linear GeC 3 Si and  4 ( σ u ) mode of linear GeC 3 Ge - PowerPoint PPT Presentation

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Identification of the  3 ( σ ) mode of linear GeC 3 Si and  4 ( σ u ) mode of linear GeC 3 Ge

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Identification of the  3 ( σ ) mode of linear GeC 3 Si and  4 ( σ u ) mode of linear GeC 3 Ge
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Identification of the  3 ( σ ) mode of linear GeC 3 Si and  4 ( σ u ) mode of linear GeC 3 Ge

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  1. Identification of the 3(σ) mode of linear GeC3Si and 4(σu) mode of linear GeC3Ge Eric Gonzalez TCU Molecular Physics Lab

  2. Motivation: • Measure far infrared modes of previous discovered molecules, • 3(σ) mode of GeC3Si and 3(σu) mode of GeC3Ge • Germanium participates in these vibrational modes, thus it could be • possible to measure germanium isotopic shifts instead of 13C shifts

  3. Germanium isotopes: 70Ge 21.23% 72Ge 27.66% 73Ge 7.73% 74Ge 35.94% 76Ge 7.44%

  4. Carbon Isotopomers for linear chains Carbon {12,13}

  5. Germanium Isotopomers for linear chains Germanium {70,72,73,74,76}

  6. One Germanium -> 5 isotopomers 70Ge 21.23% 72Ge 27.66% 73Ge 7.73% 74Ge 35.94% 76Ge 7.44%

  7. Two Germanium 15 isotopomers 70Ge 21.23% 72Ge 27.66% 73Ge 7.73% 74Ge 35.94% 76Ge 7.44% Isotopomers Probability 74Ge 72Ge 0.20 74Ge 70Ge 0.15 74Ge 74Ge 0.13 …… 76Ge 76Ge 0.006

  8. 0.092 DFT B3LYP/cc-pVDZ predicted vibrational frequencies (cm-1) and band intensities for the linear GeC3Si.

  9. Linear GeC3Si 0.01 -0.44 0.78 -0.45 0.03 ν1(σ) -0.11 0.57 0.60 0.41 -0.38 ν3(σ)

  10. 0.097 DFT B3LYP/cc-pVDZ predicted vibrational frequencies (cm-1) and band intensities for the linear GeC3Ge

  11. Linear GeC3Ge 0.01 -0.44 0.78 -0.44 0.01 ν3(σu) -0.14 0.54 0.62 0.54 -0.14 ν4(σu)

  12. Experimental Conditions: • Laser power from 2.8 to 3.3 Watts • Loose focus, beam diameter on the rod ~2/3 cm • Multiple depositions, total time between 1 and 2 hours

  13. n3 n2 n1 n3 C3 GeC3Si GeC3Ge SiC3Si 10%Ge:10%Si/100%12C, GeCSi022.ABS 1880 1900 1920 1940 1960 1980 2000 2020 2040

  14. n4 n3 n4 GeC3Ge GeC3Si SiC3Si ? ? 824.7 736.0 898.8 750 800 850 900

  15. First experiment 100% 12C/10% Si:10%Ge 824.7 825.3 825.9 824.3 823.5 824.7 825.3 826.1 825.0 824.0 815 820 825 830 835 840

  16. THEORY Second experiment: 3(σu) mode STRONG WEAK BLACKMAN-HARRIS HAMMING BOXCART BARTLET 810 815 820 825 830 835 840

  17. 74-12-12-12-28, 824.7 cm-1 3(σu) mode 73-12-12-12-28, 825.0 cm-1 72-12-12-12-28, 825.3 cm-1 70-12-12-12-28, 826.0 cm-1 76-12-12-12-28, 824.2 cm-1 A D B C E EXPERIMENT THEORY 810 815 820 825 830 835 840

  18. LP=3.5 W (first was 3.3 W) Same lenses positions 74-12-12-12-28, 824.7 cm-1 3(σ) mode 72-12-12-12-28, 825.3 cm-1 70-12-12-12-28, 826.0 cm-1 76-12-12-12-28, 824.2 cm-1 810 815 820 825 830 835 840 Frequency (cm-1)

  19. Comparison of observed vibrational frequencies (cm-1) of the 3(σ) mode for germanium isotopomers of linear GeC3Siwith the predictions of B3LYP/cc-pVDZ level calculations. aResults of the DFT-B3LYP/cc-pVDZ calculation scaled by a factor of 824.7/832.2=0.9909.

  20. n2 n3 n3 n3 C9 C6 GeC3Ge C3 experiment 10%Ge/100%12C, GeC97007.ABS 1900 1920 1940 1960 1980 2000 2020 2040

  21. First experiment 10%Ge/100%12C, GeC97007.ABS GeC3Ge 4(σu) mode 736.0 700 750 800 850 900

  22. GeC3Ge experiment 10%Ge/100%12C, GeC97007.ABS 736.0 4(σu) mode 55 min deposition, LP=3.3 W Loose focus, beam diameter on the rod ~2/3 cm 720 725 730 735 740 745 750

  23. 74-12-12-12-72, 736.0 cm-1 73-12-12-12-73 720 725 730 735 740 745 750 experiment 10%Ge/100%12C, GeC97007.ABS 4(σu) mode 74-12-12-12-74, 735.2 cm-1 76-12-12-12-72 74-12-12-12-70, 736.7 cm-1 72-12-12-12-72 72-12-12-12-70, 737.4 cm-1 76-12-12-12-74, 734.4 cm-1 deconvoluted

  24. experiment 10%Ge:10%Si/100%12C, GeC97007.ABS 74-12-12-12-72, 736.0 cm-1 73-12-12-12-73 74-12-12-12-74, 735.2 cm-1 76-12-12-12-72 74-12-12-12-70, 736.7 cm-1 72-12-12-12-72 72-12-12-12-70, 737.4 cm-1 76-12-12-12-74, 734.4 cm-1 70-12-12-12-70, 738.4 cm-1 deconvoluted 720 725 730 735 740 745 750

  25. Comparison of observed vibrational frequencies (cm-1) of the 4(σu) mode for germanium isotopomers of linear GeC3Gewith the predictions of B3LYP/cc-pVDZ level calculations. aResults of the DFT-B3LYP/cc-pVDZ calculation scaled by a factor of 736.0/741.0=0.9932.

  26. n3 n3 n3 n2 C3 C9 C6 GeC3Ge experiment 10%Ge/100%12C, GeC01011.ABS LP=2.8 W (initially 3.3W) 1900 1920 1940 1960 1980 2000 2020 2040

  27. GeC3Ge experiment 10%Ge/100%12C, GeC01011.ABS 736.0 4(σu) mode 55 min deposition, LP=2.8 W Loose focus, beam diameter on the rod ~2/3 cm Annealed at 15 K 720 725 730 735 740 745 750

  28. GeC3Ge Third experiment 10%Ge/100%12C, GeC01011.ABS 736.0 4(σu) mode Annealed at 15 K deconvoluted 720 725 730 735 740 745 750

  29. GeC3Ge experiment 10%Ge/100%12C, GeC01011.ABS 74-12-12-12-72, 736.0 cm-1 73-12-12-12-73 4(σu) mode 74-12-12-12-70, 736.7 cm-1 72-12-12-12-72 74-12-12-12-74, 735.3 cm-1 76-12-12-12-72 72-12-12-12-70, 737.5 cm-1 76-12-12-12-74, 734.5 cm-1 72-12-12-12-70, 738.3 cm-1 deconvoluted Theory, width 0.7 720 725 730 735 740 745 750

  30. Comparison of observed vibrational frequencies (cm-1) of the 4(σu) mode for germanium isotopomers of linear GeC3Gewith the predictions of B3LYP/cc-pVDZ level calculations. aResults of the DFT-B3LYP/cc-pVDZ calculation scaled by a factor of 736.0/741.0=0.9932.

  31. Conclusions • Germanium isotopic shifts were measured! • FTIR isotopic shift measurements and DFT calculations at the B3LYP/cc-pVDZ level confirm the identification of the ν3(σ) vibrational mode of linear GeC3Siat 824.7cm-1 and the ν4(σu) vibrational mode of linear GeC3Geat 736.0 cm-1.