No Access Submitted: 18 May 1998 Accepted: 14 August 1998 Published Online: 16 November 1998
J. Chem. Phys. 109, 8426 (1998); https://doi.org/10.1063/1.477505
more...View Affiliations
• Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218
View Contributors
• C. A. Fancher
• H. L. de Clercq
• O. C. Thomas
• D. W. Robinson
• K. H. Bowen
We have recorded, assigned, and analyzed the photoelectron spectrum of $ZnO−.$ The adiabatic electron affinity $(E.A.a)$ of ZnO and the vibrational frequencies of both ZnO and $ZnO−$ were determined directly from the spectrum, with a Franck–Condon analysis of its vibrational profile providing additional refinements to these parameters along with structural information. As a result, we found that $E.A.a(ZnO)=2.088±0.010 eV,$ $ωe(ZnO)=805±40 cm−1,$ $ωe(ZnO−)=625±40 cm−1,$ and that $re(ZnO−)>re(ZnO)$ by 0.07 Å. Since our measured value of $E.A.a(ZnO)$ is 0.63 eV larger than the literature value of E.A.(O), it was also evident, through a thermochemical cycle, that $D0(ZnO−)>D0(ZnO)$ by 0.63 eV. This, together with the literature value of $D0(ZnO),$ gives a value for $D0(ZnO−)$ of 2.24 eV. Since the extra electron in $ZnO−$ is expected to occupy an antibonding orbital, the combination of $D0(ZnO−)>D0(ZnO),$ $ωe(ZnO−)<ωe(ZnO),$ and $re(ZnO−)>re(ZnO)$ was initially puzzling. An explanation was provided by the calculations of Bauschlicher and Partridge, which are presented in the accompanying paper. Their work showed that our experimental findings can be understood in terms of the $a 3Π$ state of ZnO dissociating to its ground-state atoms, while the $X 1Σ+$ state of ZnO formally dissociates to a higher energy atomic asymptote.
1. 1. W. Hirschwald, in Current Topics in Materials Science, Vol. 6, edited by E. Kaldis (North Holland, Amsterdam, 1980), pp. 109–194. Google Scholar
2. 2. M. S. Chandrasekharaiah, in The Characterization of High-Temperature Vapors, edited by J. L. Margrave (Wiley, New York, 1967), pp. 495–500. Google Scholar
3. 3. S. Monticone, R. Tufeu, and A. V. Kanaev, J. Phys. Chem. B 102, 2854 (1998). Google ScholarCrossref
4. 4. L. Brewerand D. F. Mastick, J. Chem. Phys. 19, 834 (1951). Google ScholarScitation
5. 5. L. Brewer, Chem. Rev. 52, 1 (1953). Google ScholarCrossref
6. 6. W. J. Mooreand E. L. Williams, J. Phys. Chem. 63, 1516 (1959). Google ScholarCrossref
7. 7. W. J. Mooreand E. L. Williams, Discuss. Faraday Soc. 28, 86 (1959). Google ScholarCrossref
8. 8. E. A. Secco, Can. J. Chem. 38, 596 (1960). Google ScholarCrossref
9. 9. T. C. M. Pillay, J. Electrochem. Soc. 109, 76C, Abstract 134 (1962). Google ScholarCrossref
10. 10. W. Hirschwald, F. Stolze, and I. N. Stranski, Z. Phys. Chem., Neue Folge 42, S, 96 (1964). Google ScholarCrossref
11. 11. D. F. Anthropand A. W. Searcy, J. Phys. Chem. 68, 2335 (1964). Google ScholarCrossref
12. 12. B. G. Wicke, J. Chem. Phys. 78, 6036 (1983). Google ScholarScitation
13. 13. O. Gropen, U. Wahlgren, and L. Pettersson, Chem. Phys. 66, 459 (1982). Google ScholarCrossref
14. 14. C. W. Bauschlicherand S. R. Langhoff, Chem. Phys. Lett. 126, 163 (1986). Google ScholarCrossref
15. 15. M. Dolg, U. Wedig, H. Stoll, and H. Preuss, J. Chem. Phys. 86, 2123 (1987). Google ScholarScitation
16. 16. E. G. Bakalbassis, M. A.-D. Stiakaki, A. C. Tsipis, C. A. Tsipis, Chem. Phys. 205, 389 (1996). Google ScholarCrossref
17. 17. C. W. Bauschlicherand H. Partridge, J. Chem. Phys.109, 8430 (1998), following paper. Google ScholarScitation
18. 18. D. E. Clemmer, N. F. Dalleska, and P. B. Armentrout, J. Chem. Phys. 95, 7263 (1991). Google ScholarScitation
19. 19. L. R. Watson, T. L. Thiem, R. A. Dressler, R. H. Salter, and E. Murad, J. Phys. Chem. 97, 5577 (1993). Google ScholarCrossref
20. 20. E. S. Prochaskaand L. Andrews, J. Chem. Phys. 72, 6782 (1980). Google ScholarScitation
21. 21. J. V. Coe, J. T. Snodgrass, C. B. Freidhoff, K. M. McHugh, and K. H. Bowen, J. Chem. Phys. 84, 618 (1986). Google ScholarScitation
22. 22. H. W. Sarkas, J. H. Hendricks, S. T. Arnold, V. L. Slager, and K. H. Bowen, J. Chem. Phys. 100, 3358 (1994). Google ScholarScitation
23. 23. P. M. Dehmerand W. A. Chupka, J. Chem. Phys. 62, 4525 (1975). Google ScholarScitation
24. 24. K. M. Ervin and W. C. Lineberger, in Advances in Gas Phase Ion Chemistry, Vol. I, edited by N. G. Adams and L. M. Babcock (JAI, Greenwich, 1992). Google Scholar
25. 25. PESCAL Fortran program, written by K. M. Ervin and W. C. Lineberger. Google Scholar
26. 26. “Because the reaction of $Zn+(2S)+NO2(2A)→ZnO(1Σ+)+NO+(1Σ+)$ is spin-allowed, formation of the ZnO ground state at the threshold for reaction is expected” (P. B. Armentrout, private communication). Google Scholar
1. © 1998 American Institute of Physics.