1. Proton Stretch in H 4 O 2 + : Effect of Ar Jheng-Wei Li, Ying-Cheng Li, Kaito Takahashi and Jer-Lai Kuo Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan FC02 @ 70 th OSU Int. Symp. on Mol. Spectroscopy, University of Illinois Urbana-Champaign, USA, June/26/2015

2. Structural Evolution & Solvation of OH radical in (H 2 O) n +, n=5~8 En-Ping Lu, Piin-Ruey Pan, Ying-Cheng Li and Jer-Lai Kuo Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan Ming-Kang Tsai Dept of Chem., National Taiwan Normal University, Taipei, Taiwan RG02 @ 69 th OSU Int. Symp. on Mol. Spectroscopy, University of Illinois Urbana-Champaign, USA, June/19/2014

3. (H 2 O) n + vs. H + (H 2 O) n Mizuse, Kuo, Fujii, Chem. Sci., 2, 868 (2011)

4. IR Spectra of (H 2 O) n +, n=5~8 Vib. band ~ 3200 cm -1 is assigned to fully solvated OH. Direct evidence of solvated OH radical for n ≥ 7.

5. Protonated Water Dimer Cation: H 5 O 2 + IHB vibration = the doublet ~ 1000 cm -1 Full Dimensional Calculations on Joe Bowman’s PES@CCSD(T)/aTZ

6. Water Dimer Cation: H 4 O 2 + IHB vibration = Multiple intense peaks ~2000 cm -1 For IHB, is Argon relevant ? Triplet rather than a single peak. H 4 O 2 + Ar 2 H 4 O 2 + Ar 1 Schaefer, H. F. et al. J. Phys. Chem. A 2009, 113, 13779 Johnson, M. A. et al. J. Phys. Chem. A 2009, 113, 4772

7. Outline Quick review on theoretical works Methodology Results Summary 7

8. Previous theoretical works - I E. Kamarchik, O. Kostko, Joel M. Bowman, M. Ahmed, and A. I. Krylov J. Phys. Chem. A, 113, 4772 (2009) PES is obtained by MP2/aug-cc-pVDZ (a) the outer bonds in H3O+ (b) the OO bond length, (c) the HOH angle (i.e., of the outer OH bonds in H3O+) (d) the dihedral angle corresponding to the orientation of the OH moiety

9. Previous theoretical works - II J. Chem. Phys., 132, 194311 (2010) PES is obtained with EOM-IP-CCSD/aug-cc-pVTZ IR spectra were done computed Presence of Ar is not included

10. Normal Mode Approx. (NMA) A simple DVR along normal mode direction (approx.) PES obtained from ab initio cal. (no approx.) Diagonalize the (no approx.) Intensities were calculated via Fermi Golden Rule (no approx.) We use harmonic grids on B3LYP/6-31+G(d,p)

11. Stretches(4D) Bends+Stretches(6D) Anharmonicity in H 3 O +..OH· Harm. 11

12. Effect of Ar on H + stretch (Structure) 2.4902.5072.522 2.396 1.199 1.0721.035 1.028 0.991

13. OH radical Sym & Asym. Effect of Ar on H + stretch (Vib. Spectra) 6D (3 d(OH) + H + strech + 2 bends)

14. OH radical Sym & Asym. Effect of Ar on H + stretch (Vib. Spectra) 6D (3 d(OH) + H + strech + 2 bends)

15. Low-freq. vibrational modes 118cm -1 385cm -1 411cm -1 486cm -1 612cm -1 973cm -1

16. Possible origins of “Triplet” 114cm -1 965cm -1 113cm -1 961cm -1

17. What else? Location of Ar n=2 E = -1206.1010 Eh ZPE = -1206.0539 Eh E = -1206.0989 Eh ZPE = -1206.0521 Eh 2A 2B 2C E = -1206.0989 Eh ZPE = -1206.0521 Eh n=1 E = -679.1286 Eh ZPE = -679.0822 Eh E = -679.1265 Eh ZPE = -679.0806 Eh E = -679.1286 Eh ZPE = -679.0822 Eh 1A1C 1B 1A 1B

18. Summary Vibrational spectra of H 4 O 2 +..Ar 0,1&2 were computed. Strong coupling with two bending modes were found. A few low freq – vibrational modes are important too. Vibrational feature ~ 2000 cm -1 is sensitive to the position of Ar. Call for more exp. (Ne/He-tagged & 3 Ar-tagged) & full dimensional calculations on high quality PES.