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Reply to comments on “the chemisorption and decomposition of NO on the (110) surface of iridium”
Surface Science North-Holland
L522
SURFACE
SCIENCE
LETTERS
REPLY TO COMMENTS ON “THE CHEMISORPTION DECOMPOSITION OF NO ON THE (110) SURFACE D.E. IBBOTSON
121 (1982) L522-L523 Publishing Company
*, T.S. WITTRIG
AND OF IRIDIUM”
** and W.H. WEINBERG
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA Received
14 June 1982
and Baker [l], it is stated that our In the previous Letter of Klauber assignment of the 58 and Iii orbitals is not possible from the UPS data presented in a recent paper [2] for NO on Ir( 1 lo)-( 1 X 2). Rather, they suggest our separate assignment of the 56 and iii orbitals as 10.4 and 8.5 eV below E, should be (56 + 17j) or singlet and triplet 5d(‘II, 311). However, we believe our original assignment is both correct and quite reasonable by examining our data more closely and combining it with the corrected interpretation of Kanski and Rhodin [ 1,3]. First, our data concerning the UPS of NO on Ir(1 lo)-(1 X 2) is only a small fraction of the entire study of this system [2]. Second, Klauber and Baker did not include additional data from our paper [2] which show that the two levels at 10.4 and 8.5 eV are independent of one another. Namely, the preadsorption of oxygen on Ir( 1 lo)-( 1 X 2) either in oxide form or not, causes the level at 8.5 eV to shift to higher BE, leaving the level at 10.4 eV unshifted. This information alone shows these to be independent levels and not singlet and triplet states of the 5d orbital. Third, the assignment of Kanski and Rhodin [3], corrected by Klauber and Baker in their Letter, based on relative orbital intensities using the He1 and He11 radiation further supports our assignment that the BE of 56 > 175, and distinct. Finally, Batra and Brundle [4] observe discrete levels for the 5a’ and iii orbitals with the same ordering for NO on polycrystalline Ni as for Ir [2,3], and the position of the 56 orbital has been independently verified recently by Penning ionization [5] for NO on Ni(ll1). In summary, Klauber and Baker have done an extensive and critical survey of the UPS of NO chemisorbed on a number of the transition metals, which is quite admirable. However, their discussion of our data for NO on Ir( 1 lo)-( 1 X 2) is flawed, the original discussion [2] being the correct interpretation. * Present ** Present
address: address:
Bell Telephone Laboratories, Murray Hill, New Jersey 07974, USA. Amoco Research Center, Naperville, Illinois 60566, USA.
0039-6028/82/f)OOO-O/$02.75
0 1982 North-Holland
D.E. Ibbotson et al. / Chemisorption
This research was supported Grant No. CHE77-16314.
and decomposition
by the National
of NO
Science Foundation
References [l] [2] [3] [4] [5]
C. Klauber and B.G. Baker, Surface Sci. 121 (1982) L513. D.E. Ibbotson, T.S. Wittrig and W.H. Weinberg, Surface Sci. 110 (1981) 294. J. Kanski and T.N. Rhodin, Surface Sci. 65 (1977) 63. I.P. Batra and C.R. Brundle, Surface Sci. 57 (1976) 12. J. Roussel, C. Boisiau, R. Nuvolone and C. Reynaud, Surface Sci. 110 (1981) L634.
IS23
under
L522
SURFACE
SCIENCE
LETTERS
REPLY TO COMMENTS ON “THE CHEMISORPTION DECOMPOSITION OF NO ON THE (110) SURFACE D.E. IBBOTSON
121 (1982) L522-L523 Publishing Company
*, T.S. WITTRIG
AND OF IRIDIUM”
** and W.H. WEINBERG
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA Received
14 June 1982
and Baker [l], it is stated that our In the previous Letter of Klauber assignment of the 58 and Iii orbitals is not possible from the UPS data presented in a recent paper [2] for NO on Ir( 1 lo)-( 1 X 2). Rather, they suggest our separate assignment of the 56 and iii orbitals as 10.4 and 8.5 eV below E, should be (56 + 17j) or singlet and triplet 5d(‘II, 311). However, we believe our original assignment is both correct and quite reasonable by examining our data more closely and combining it with the corrected interpretation of Kanski and Rhodin [ 1,3]. First, our data concerning the UPS of NO on Ir(1 lo)-(1 X 2) is only a small fraction of the entire study of this system [2]. Second, Klauber and Baker did not include additional data from our paper [2] which show that the two levels at 10.4 and 8.5 eV are independent of one another. Namely, the preadsorption of oxygen on Ir( 1 lo)-( 1 X 2) either in oxide form or not, causes the level at 8.5 eV to shift to higher BE, leaving the level at 10.4 eV unshifted. This information alone shows these to be independent levels and not singlet and triplet states of the 5d orbital. Third, the assignment of Kanski and Rhodin [3], corrected by Klauber and Baker in their Letter, based on relative orbital intensities using the He1 and He11 radiation further supports our assignment that the BE of 56 > 175, and distinct. Finally, Batra and Brundle [4] observe discrete levels for the 5a’ and iii orbitals with the same ordering for NO on polycrystalline Ni as for Ir [2,3], and the position of the 56 orbital has been independently verified recently by Penning ionization [5] for NO on Ni(ll1). In summary, Klauber and Baker have done an extensive and critical survey of the UPS of NO chemisorbed on a number of the transition metals, which is quite admirable. However, their discussion of our data for NO on Ir( 1 lo)-( 1 X 2) is flawed, the original discussion [2] being the correct interpretation. * Present ** Present
address: address:
Bell Telephone Laboratories, Murray Hill, New Jersey 07974, USA. Amoco Research Center, Naperville, Illinois 60566, USA.
0039-6028/82/f)OOO-O/$02.75
0 1982 North-Holland
D.E. Ibbotson et al. / Chemisorption
This research was supported Grant No. CHE77-16314.
and decomposition
by the National
of NO
Science Foundation
References [l] [2] [3] [4] [5]
C. Klauber and B.G. Baker, Surface Sci. 121 (1982) L513. D.E. Ibbotson, T.S. Wittrig and W.H. Weinberg, Surface Sci. 110 (1981) 294. J. Kanski and T.N. Rhodin, Surface Sci. 65 (1977) 63. I.P. Batra and C.R. Brundle, Surface Sci. 57 (1976) 12. J. Roussel, C. Boisiau, R. Nuvolone and C. Reynaud, Surface Sci. 110 (1981) L634.
IS23
under