1. Wei Li, Mingfei Zhou Fudan University , Shanghai, China
Infrared Spectroscopic and Theoretical Study of the HCnO+ (n = 5-12) Cations
Wei Li, Mingfei Zhou
Fudan University , Shanghai, China
Talk FA09, 72th ISMS, June 2017

2. Content 1. Background 2. Experimental and Computational Methods
3. Results and discussion
4. Conclusions

3. Background Carbon chains and derivatives
Potential interstellar molecules
Highly active species
Reactive intermediates
H. Herrmann, et al. J. Atmos.Chem. 2000, 36, 231
D. L. Baulch, et al. J. Phys. Chem. 2005, 34, 757
P. Ehrenfreund, et al. Annu. Rev. Astron. Astrophys. 2000, 38, 427

4. Background Spectroscopy Rotational spectra HC5O and HC7O radicals
HCnO (n = 1-9)
Mass spectrometry
HCnO+ ions
Electronic spectra
HC7O+ cation
S. Mohamed, et al. J. Chem. Phys. 2005, 123,
A.C.Simmonett, et al. J.Phys.Chem.A.2009,113,11643
S. Peppe, et al. J. Phys. Chem. A. 2000, 104, 5817
A. Chakraborty, et al. Mol. Phys. 2016, 114, 2794

5. Experimental Method AB+ ~ l IR photodissociation spectrum
G. J. Wang, et al. J. Phys. Chem.A. 2012, 116, 2484
G. J. Wang, et al. Sci. China: Chem. 2014, 57, 172

6. Computational Method Geometries and frequencies B3LYP-D3 Aug-cc-pVTZ
Scale factor 0.968
Bonding analyses
Natural orbital analysis(NBO)
Adaptive natural density partitioning(AdNDP)
A. E. Reed, et al. J. Chem. Phys. 1985, 83, 735
D. Y. Zubarev, et al. Phys. Chem. Chem. Phys. 2008, 10, 5207

7. Mass spectrum
C + CO/H2/He
HCnO+ (n = 5-12)
[HCnO·CO]+ (n = 5-12)

8. IR photodissociation spectra of [HCnO·CO]+
C-C
C-O
C-H
n = 5
n = 7
n = 9
n = 11
n = 6
n = 8
n = 10
n = 12

9. The stability of linear carbon chain cations
HC5O+
(e) 1A1 ; C2v; ΔE = 58.7 kcal/mol
(d) 3Σ-; C∞V; ΔE = 56.7 kcal/mol
(c) 1A ; Cs; ΔE = 55.9 kcal/mol
(b) 1A ; Cs; ΔE = 54.7 kcal/mol
(a) 1Σ+; C∞V; ΔE = 0.0 kcal/mol

10. Negligible effect of CO-tagging
(b) 1Σ+ [HC5O]+ (C∞V)
(a) 1A [HC5O·CO]+ (Cs)

11. Geometries and NBO analyses
[HCnO]+ (n = 5,7,9,11); 1Σ+; C∞V
Polyyne-like structures
n = 5
n = 7
n = 9
n = 11
*Bond lengths in angstroms and Wiberg bond orders (values in brackets)

12. Geometries and NBO analyses
[HCnO]+ (n = 6,8,10,12); 3Σ-;C∞V
allene-like structures
n = 8
n = 10
n = 12
*Bond lengths in angstroms and Wiberg bond orders (values in brackets)

13. AdNDP
1×1c-2e LPs
ON=|1.98e|
2×3c-2e π
ON=|2.00e|
2×4c-2e π
ON=|2.00e|
6×2c-2e σ
ON=|1.99e-2.00e|
2×6c-2e π
ON=|2.00e|
The adaptive natural density partitioning analyses (AdNDP) of HC5O+

14. Conclusions
The HCnO+ (n = 5-12) core cations are characterized to be linear carbon chain derivatives terminated by hydrogen and oxygen.
The HCnO+ cations with odd n have closed-shell singlet ground states with polyyne-like structures, while those with even n have triplet ground states with allene-like structures.
The AdNDP bonding analysis indicates that along with the localized two-center-two-electron  bonds, there are pairs of multiple-center-two-electron delocalized π bonds on the CnO chains.

15. Acknowledgment Advisor: Prof. Mingfei Zhou Zhou Group:
Dr. Guanjun Wang
Jiaye Jin

16. Thank you very much for your attention!

17. Q&A n=5 n=7 Structure Experimental (black) and simulated
(c)1Σ+ [HC5O]+ (C∞V)
n=5
(b) 1A [HC5O·CO]+ (Cs)
(c)1Σ+ [HC7O]+ (C∞V)
n=7
Experimental (black) and simulated
(red) vibrational spectra
(b) 1A [HC7O·CO]+ (Cs)
Structure

18. Q&A n=9 n=11 Structure Experimental (black) and simulated
(c)1Σ+ [HC9O]+ (C∞V)
n=9
(b) 1A [HC9O·CO]+ (Cs)
n=11
(c)1Σ+ [HC11O]+ (C∞V)
Experimental (black) and simulated
(red) vibrational spectra
(b) 1A [HC11O·CO]+ (Cs)
Structure

19. Q&A n=6 n=8 Structure Experimental (black) and simulated
(d)3Σ- [HC6O]+ (C∞V)
n=6
(c)3A [HC6O·CO]+ (Cs)
(b)3Σ- [HC6O·CO]+ (C∞V)
n=8
(c)3Σ- [HC8O]+ (C∞V)
Experimental (black) and simulated
(red) vibrational spectra
(b)3A [HC8O·CO]+ (Cs)
Structure

20. Q&A n=10 n=12 Structure Experimental (black) and simulated
(c)3Σ- [HC10O]+ (C∞V)
n=10
(b)3A [HC10O·CO]+ (Cs)
(c)3Σ- [HC12O]+ (C∞V)
n=12
(b)3A [HC12O·CO]+ (Cs)
Experimental (black) and simulated
(red) vibrational spectra
Structure

21. Q&A
The adaptive natural density partitioning analyses (AdNDP) of HC6O+
The adaptive natural density partitioning analyses (AdNDP) of HC8O+
The adaptive natural density partitioning analyses (AdNDP) of HC10O+
The adaptive natural density partitioning analyses (AdNDP) of HC12O+

22. Q&A
The adaptive natural density partitioning analyses (AdNDP) of HC7O+
The adaptive natural density partitioning analyses (AdNDP) of HC9O+
The adaptive natural density partitioning analyses (AdNDP) of HC11O+