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Photoelectron spectra of hydrogen peroxide and hydrogen disulphide: ab initio calculations
Volume 28, number 4
._
:
15 OCtObei 1974
:
CHEMlCAL PHYSICS LETTlSRS
.,
:-
:
‘,. .
‘_
:
PHOTOELECTRON SPE&A OF iiYDRO@~N PEROXIDE. AND; WDROGi3 DI§ejLPHIDE:.AB’IN:iTIO CALCULAT!~NS pw. DAvtis Department of CJ~emis~ry, Univmity R,eceivcd
BimingJ~ah B15 2TT, UK
of @in&yhmn. 3 June 1974
Kooprnans’ theorem ionization potenti& from ab initio &~~sivl b;&s-t calculations on cis, tram and ske:v fofls of HOOH and HSSH ae cornpar@ with e);perimental values from phoioe!ectron spectroscopy.
Osafune’and Kimura [I ] have recently published the.experimental,photoelectron spectrum of HOOH, and interpreted it on the basis of CNDO/Z calculations. Similar work has been done on dtrivatives of HsfSH by other.wofkers [2-S]. ,A sounder basis for interpreting the spectra is provided .by ab initio self-consistent m6lecular orbital calculations. The obj&t of this note is to report the results of some calculations with a contracted gaussian Ibasis set of the double zeta plus polarization type.on @, rrans and skew’forms of HOOH and I%SH. Although there are several ab initio c+latiofis on these molecules in the literature [6], the results have not ‘bden used to‘inteipret the photoelectron spectra, +d the eigenvectors and eigenvalues for the largest basis sets ue not quoted. Ail computations were made with the .+TMOL piogramke on the University of Birmingham 1906A and Atlas Laboratory IBM 3701195 amputers. The contracted gaussian orbit& used, with type and number of cqntributing functions (in brackets)‘were: H 43, I),‘pW, totd 5; 0 @,4,2, I), ~(4, I), d(% totaI~16;Ss(6,Z!,l,l,l,I),p(6,1,1,1),d(l),total ..24. The coefficients tid exponents used for H.and 0 &e given by Snyder and Basch [7], and for-S by Veillard [S]. The exponent 0.75 was’,tised for the ‘p-orbital on H, and the eJcponent 0.6 for the d-orb% takon Cl and S. Similar calculations with different:,. .‘exponents have been made by Dunning and Winter for HOOH i9] and with a different choice of’contreutions+y Veillard’and @emuynck.For HS$,H [ 101, ‘_..
Table 1
Geometries for HO’OH and HSSH Irngths
‘Angles (deg.)
(au).
x
XII
xx
LXXH
dihedral (skew!
0
1.788
2.632 3.883388
1025 91.35
113.7 90.6
s
2.507668
. .
Table 2
,’ -L--
: Total energies(au)
.-
,+ skew trnrrr ‘,
HOOH.’
HSSH
-150.789225. -150.80?921 -150.801776
-796.168395 -796.201512 -796.194691
.
The geometries used i? the present calculations and the total energies obtained are given in tables 1 and 2. For the tram form of HOOH the energy is OIO2au higher than the vaiue given by Dunning and Winter ,;9], and for the tram form of -HSSH the energy is 0.02 au lower than the value given by Veillard and Demuynck [lo]. The ~?ooprrians’ theoreti ionization potentials are -. shown in tables 3 and 4. The conventional symmetry : qecies :$r tithecis (C,,), skew (C,) and rrans (C&J &-II-IS are @ien, as well as a symbol indicat@g the majo’r c,J@ribut$g p symmetry orbital in a fixed cobrdinati: system. The &IX& is along the central bdnd, and the two tintral atoms and one H atom are always in theyz pIa&. thus X-, for &ti@e, is,the gerade. : .
‘.
Volume 28, number 4
CHEMICAL. PHYSICS LETl-ERS
Koopmans’ C& 2P
2s
a2
‘.
b2 31 bl 31
12.20 15.61 16.74 17.48 21.42
b2
32.92
31
41.12
(x-j (y-) (z_) (x3 (_v?
Table 3 theorem ionization poteritials
for HOOH (eV)
Skerv(lL3.79
27ms
4b
%
4a 3b 3a
12.88 13.84 16.92 (2’) 1.9.48 19.91
2b 2a
32.90 40.91
5a
1s
as au % h
hl
%
hpt. 12.06 14.56 17.33 18.90 19.91
(r-) Q-z) (r’> (y-z-) (y+)
[I].
LL.69 12.69 15.33 17.4 17.4
32.88 40.83
561(2)
Koopmans’
3P
9.04 (J_)
12.65 13.25 13.61 17.13
(x3 (z-y? (y_) (z-y?
29.22 2s
0b 9a 8a ,7b 7a
6b
24.13 181.5(6)
Table 4 theorem ionization potentials
6a 244.5(2)
IS
mmbination of pX orbitals on the.0 or S atoms, and is a n-orbital in the cis and tram forms. This orbital is essentially non-bonding in the cis and trms forms. With a dihedral angle of 90” it is approximately degenerate with they- orbital. The xf and y+ orbit& have more bonding character, and are degenerate for a larger angle than 90’. In both molecules the highest zorbital changes little in energy between cis and skew forms; but mixes strongly with they- orbital in the ttxme form. Case is needed in corre!atiig the cis and rrans orbitals, as an a species orbital in C2, wn become eitheraorbinC2.,.’ The a6 initio results differ in some respects from the CND0/2 results.[l]. The 1 eV splitting ofthe 4b, Sa pair and the 0.4 eV sphtting of the 3b, 3a pair for HOOH shown in table 3 is in better agreement with experiment than the CNDO/Z results, which show ,alarger spbtt,ing for the 3b, 3a pair. For HSSH, in which the dihedral angle is close to 90°, the ab iritio calculations lead to a prediction of a
for HSSH
?hns
Skew (90.6’)
cir
2P
1: October 1974
10.45 10.45 13.20 (z_) 15.31 16.16
% ag alI % bu
9.02 1255 12.63 15.2L 16.05
24.16
bu
29.12 2503(2)
“6
24.24 29.12
(x7 (Z-J (x+) (Z-J Q3
zero splitting fdr the top 8b, 9a pair, and 0.8 eV splitting for the 7b, 73 pair. Experimental results for FSSF 133, in which the dihedral angle is 87.9O, give a splitting of 0.4 eV for the top-most pair, the lowest ‘ionization potentials being 10.84 and 11.25. In ClSSC1[5], no splitting was observed for the lowest jonization potential at ‘10.21 eV. In CH,SSCHs [4], the splitting is 0.24 eV, the two lowest ionization potentials being 8.37 and 9.21. In general, the calculations give a lower first iotiation potential for HSSH than for HOOH, which the experimental values also LnpIy. For HSSH the calculated values are more reliable than for HOOH, as there should be l&s rearrangement on io~tiation. The spectrum of HSSK when measured is Likety to be close to the values given in table.4 for the skew form. The author is indebted to Dr. J. Burdon for some : -.useful discussions.
,,: 15,; O+qber-1.&j.’ ” .- .: ). ;.. I6)‘j~.cl.Richards;.T:E;H. Walk&d ti.K: .j&c& : A bibliography qf ab.htio moikculax wavefuriciions:’ ._. .’ fOx%rd,l969) pp.: 1-54,155; -. _: ,. .,, ..’ H.F. Schaefir, n& e~~~~~~ s&w&e of at’o& a$ :. :_. : :. ‘l.. . (1974) 47.: ,, . D.C. Frqst.arad DA_;V@rn, Ino& Cbe&. I I ::. .” 11: mobicules (Addii?n~W&ley; Readi& 1972)~. 404, ,’ &?]~W.R~Culle’ri, fl]’ LX. Sriydgr and’% Bas&, Mo1ccula.r~a~efun~iu~ and’ ,: _: 8.0969) 1803.. . prbperti$05Tilcy, New York, 1972) p” 24. ‘, ‘:[3] .G. Wag&, H. Bock, R Bud& +nd F. Se+ ihem. Ber: ‘.,.,. 106,f1973)‘1285. ‘[S] &J’eiUard, Theoret. Chin-~.Acta 12. (19fiR) 4d5. ‘,. : : [?I (&i,.194T H. Ifunning .,) arid,.IN.W. Winter, : Chcm. Phys * Letiers II . : ‘. @I P-J, Roberts, p+te ~rnmu~~~on (1974). .. ‘1 _, [lo] A., Veillard hnd 3.’De&y&k, Chem, Phgs. Letters 4 .’ (1969)476_ ‘, : ,., .- ,_ ‘. ‘. -. ,: ., ; ” ,’ ‘i ; ‘. .., .’ ,* .,‘. ._ ‘. ,,. :.. : ,. ‘:, .: ., ‘. ;: : ; ..’ _; 1 : ‘,, :.:. ..: : “. :. ,. ). ,” .: ,‘. ._ . ... .,,, “,:. :. I.,‘~ ., ..‘. ., ,,:., :-.’ ,.. .. ., ,. : : .,I ,, -_: ‘,. _. ._ .“, ...: _; ‘.. ._ ‘( .,: ” :. ._..’ : ‘:‘ ..__ .. (,‘. ‘. : ‘( ‘, : ,. ” ‘, . ,, : ,.. ‘: ,, .,’ .“‘. ,’ .,,, ,, .“, .’ ,, .,’ “,: ., ,’ .” ,‘. I, ,” _/.. ) . ,‘, . ., ., 0, ,’ ‘, ,-_ ,~ _ ,,I .. I .. : ,, :- .- ..’ : ; .“,.’ . ” ‘(’ ‘I,‘.j, .’ ‘_ ; ‘. .,: ” ._ .. ,‘ ’ ..‘, ,, ,_ ., 1: :. ..‘. .‘. ._..‘” _ : ,: ..;’ _. r. ‘,_ ._ _. _..’ ., ‘.’ ,“. ,‘, ,, (~ ‘.’ ‘, ,. .’ _,,_’ .’ : .,,, 1, _‘-’ ,,_ ;. ‘. ~ ;. ,,.’ “. 1 ,_’ .’ ,: ‘. ., “. ‘. ; _‘.(’ ,.y ,, ,, (. )I. :..; .-, ,; .,. ;’ “, .’ ,,’ :.. . ,. ._ . .., : -.. (, :_ .. .. I’ ‘,,._. , ., .. :.,. ” : ‘_ ‘.‘. ,.; (. ., _;,. ‘,” ‘. .. ” .., .‘( : ‘. .,, .” .: :.“. ,. ‘:;‘, ” ., ; .. _.‘. .., ‘. ..,’ (.’ .‘, ,I.,. -’ .: .’ : _, . ‘, ,, ‘, ‘) ; _.“_ ,‘.,‘. ‘.’ .: ., ‘. ‘: ‘. _, . ‘. ‘. ,.. -. .,.I . ,‘, ‘. ” ,’ .’ :., .’ ,.;, ,(.. ‘,,.. ‘. ;. ,.‘. ., ., : ,*I .. . . _’ ,,. ._ ._ .. . ,. __‘. ,. .; (.._ .’ ; ..‘,. ‘. ‘, ., .;, ‘., .’ _.. ” ,( ‘; (. ‘, ‘. _ ,, _. ‘~ ,, . . : ‘, ‘, . ,../ ,’ ..’ .,’ ‘., ,’ ‘, ‘. .. . _’ ” ;, ,_ ‘J : ._ ,, “. ,, ‘,,. ,_ :‘:. ‘_,‘,. (,’ ” ‘. ...‘, ,..’ ,. ._:. ,: . ‘, .( .: .‘,, .:.. ,‘,. ‘: ), ., ,, ‘. ,:’ “. ‘..‘.‘. ‘.-, : ‘. ,: .:. _’ ... ~:_:;~oluinc28, gT.$ber 4 -.. -.- : .I._ ,,‘. ‘,.
y:, .- I.’ ._:‘. :-,:, -. : ., :: :* ‘, :.
._
:
15 OCtObei 1974
:
CHEMlCAL PHYSICS LETTlSRS
.,
:-
:
‘,. .
‘_
:
PHOTOELECTRON SPE&A OF iiYDRO@~N PEROXIDE. AND; WDROGi3 DI§ejLPHIDE:.AB’IN:iTIO CALCULAT!~NS pw. DAvtis Department of CJ~emis~ry, Univmity R,eceivcd
BimingJ~ah B15 2TT, UK
of @in&yhmn. 3 June 1974
Kooprnans’ theorem ionization potenti& from ab initio &~~sivl b;&s-t calculations on cis, tram and ske:v fofls of HOOH and HSSH ae cornpar@ with e);perimental values from phoioe!ectron spectroscopy.
Osafune’and Kimura [I ] have recently published the.experimental,photoelectron spectrum of HOOH, and interpreted it on the basis of CNDO/Z calculations. Similar work has been done on dtrivatives of HsfSH by other.wofkers [2-S]. ,A sounder basis for interpreting the spectra is provided .by ab initio self-consistent m6lecular orbital calculations. The obj&t of this note is to report the results of some calculations with a contracted gaussian Ibasis set of the double zeta plus polarization type.on @, rrans and skew’forms of HOOH and I%SH. Although there are several ab initio c+latiofis on these molecules in the literature [6], the results have not ‘bden used to‘inteipret the photoelectron spectra, +d the eigenvectors and eigenvalues for the largest basis sets ue not quoted. Ail computations were made with the .+TMOL piogramke on the University of Birmingham 1906A and Atlas Laboratory IBM 3701195 amputers. The contracted gaussian orbit& used, with type and number of cqntributing functions (in brackets)‘were: H 43, I),‘pW, totd 5; 0 @,4,2, I), ~(4, I), d(% totaI~16;Ss(6,Z!,l,l,l,I),p(6,1,1,1),d(l),total ..24. The coefficients tid exponents used for H.and 0 &e given by Snyder and Basch [7], and for-S by Veillard [S]. The exponent 0.75 was’,tised for the ‘p-orbital on H, and the eJcponent 0.6 for the d-orb% takon Cl and S. Similar calculations with different:,. .‘exponents have been made by Dunning and Winter for HOOH i9] and with a different choice of’contreutions+y Veillard’and @emuynck.For HS$,H [ 101, ‘_..
Table 1
Geometries for HO’OH and HSSH Irngths
‘Angles (deg.)
(au).
x
XII
xx
LXXH
dihedral (skew!
0
1.788
2.632 3.883388
1025 91.35
113.7 90.6
s
2.507668
. .
Table 2
,’ -L--
: Total energies(au)
.-
,+ skew trnrrr ‘,
HOOH.’
HSSH
-150.789225. -150.80?921 -150.801776
-796.168395 -796.201512 -796.194691
.
The geometries used i? the present calculations and the total energies obtained are given in tables 1 and 2. For the tram form of HOOH the energy is OIO2au higher than the vaiue given by Dunning and Winter ,;9], and for the tram form of -HSSH the energy is 0.02 au lower than the value given by Veillard and Demuynck [lo]. The ~?ooprrians’ theoreti ionization potentials are -. shown in tables 3 and 4. The conventional symmetry : qecies :$r tithecis (C,,), skew (C,) and rrans (C&J &-II-IS are @ien, as well as a symbol indicat@g the majo’r c,J@ribut$g p symmetry orbital in a fixed cobrdinati: system. The &IX& is along the central bdnd, and the two tintral atoms and one H atom are always in theyz pIa&. thus X-, for &ti@e, is,the gerade. : .
‘.
Volume 28, number 4
CHEMICAL. PHYSICS LETl-ERS
Koopmans’ C& 2P
2s
a2
‘.
b2 31 bl 31
12.20 15.61 16.74 17.48 21.42
b2
32.92
31
41.12
(x-j (y-) (z_) (x3 (_v?
Table 3 theorem ionization poteritials
for HOOH (eV)
Skerv(lL3.79
27ms
4b
%
4a 3b 3a
12.88 13.84 16.92 (2’) 1.9.48 19.91
2b 2a
32.90 40.91
5a
1s
as au % h
hl
%
hpt. 12.06 14.56 17.33 18.90 19.91
(r-) Q-z) (r’> (y-z-) (y+)
[I].
LL.69 12.69 15.33 17.4 17.4
32.88 40.83
561(2)
Koopmans’
3P
9.04 (J_)
12.65 13.25 13.61 17.13
(x3 (z-y? (y_) (z-y?
29.22 2s
0b 9a 8a ,7b 7a
6b
24.13 181.5(6)
Table 4 theorem ionization potentials
6a 244.5(2)
IS
mmbination of pX orbitals on the.0 or S atoms, and is a n-orbital in the cis and tram forms. This orbital is essentially non-bonding in the cis and trms forms. With a dihedral angle of 90” it is approximately degenerate with they- orbital. The xf and y+ orbit& have more bonding character, and are degenerate for a larger angle than 90’. In both molecules the highest zorbital changes little in energy between cis and skew forms; but mixes strongly with they- orbital in the ttxme form. Case is needed in corre!atiig the cis and rrans orbitals, as an a species orbital in C2, wn become eitheraorbinC2.,.’ The a6 initio results differ in some respects from the CND0/2 results.[l]. The 1 eV splitting ofthe 4b, Sa pair and the 0.4 eV sphtting of the 3b, 3a pair for HOOH shown in table 3 is in better agreement with experiment than the CNDO/Z results, which show ,alarger spbtt,ing for the 3b, 3a pair. For HSSH, in which the dihedral angle is close to 90°, the ab iritio calculations lead to a prediction of a
for HSSH
?hns
Skew (90.6’)
cir
2P
1: October 1974
10.45 10.45 13.20 (z_) 15.31 16.16
% ag alI % bu
9.02 1255 12.63 15.2L 16.05
24.16
bu
29.12 2503(2)
“6
24.24 29.12
(x7 (Z-J (x+) (Z-J Q3
zero splitting fdr the top 8b, 9a pair, and 0.8 eV splitting for the 7b, 73 pair. Experimental results for FSSF 133, in which the dihedral angle is 87.9O, give a splitting of 0.4 eV for the top-most pair, the lowest ‘ionization potentials being 10.84 and 11.25. In ClSSC1[5], no splitting was observed for the lowest jonization potential at ‘10.21 eV. In CH,SSCHs [4], the splitting is 0.24 eV, the two lowest ionization potentials being 8.37 and 9.21. In general, the calculations give a lower first iotiation potential for HSSH than for HOOH, which the experimental values also LnpIy. For HSSH the calculated values are more reliable than for HOOH, as there should be l&s rearrangement on io~tiation. The spectrum of HSSK when measured is Likety to be close to the values given in table.4 for the skew form. The author is indebted to Dr. J. Burdon for some : -.useful discussions.
,,: 15,; O+qber-1.&j.’ ” .- .: ). ;.. I6)‘j~.cl.Richards;.T:E;H. Walk&d ti.K: .j&c& : A bibliography qf ab.htio moikculax wavefuriciions:’ ._. .’ fOx%rd,l969) pp.: 1-54,155; -. _: ,. .,, ..’ H.F. Schaefir, n& e~~~~~~ s&w&e of at’o& a$ :. :_. : :. ‘l.. . (1974) 47.: ,, . D.C. Frqst.arad DA_;V@rn, Ino& Cbe&. I I ::. .” 11: mobicules (Addii?n~W&ley; Readi& 1972)~. 404, ,’ &?]~W.R~Culle’ri, fl]’ LX. Sriydgr and’% Bas&, Mo1ccula.r~a~efun~iu~ and’ ,: _: 8.0969) 1803.. . prbperti$05Tilcy, New York, 1972) p” 24. ‘, ‘:[3] .G. Wag&, H. Bock, R Bud& +nd F. Se+ ihem. Ber: ‘.,.,. 106,f1973)‘1285. ‘[S] &J’eiUard, Theoret. Chin-~.Acta 12. (19fiR) 4d5. ‘,. : : [?I (&i,.194T H. Ifunning .,) arid,.IN.W. Winter, : Chcm. Phys * Letiers II . : ‘. @I P-J, Roberts, p+te ~rnmu~~~on (1974). .. ‘1 _, [lo] A., Veillard hnd 3.’De&y&k, Chem, Phgs. Letters 4 .’ (1969)476_ ‘, : ,., .- ,_ ‘. ‘. -. ,: ., ; ” ,’ ‘i ; ‘. .., .’ ,* .,‘. ._ ‘. ,,. :.. : ,. ‘:, .: ., ‘. ;: : ; ..’ _; 1 : ‘,, :.:. ..: : “. :. ,. ). ,” .: ,‘. ._ . ... .,,, “,:. :. I.,‘~ ., ..‘. ., ,,:., :-.’ ,.. .. ., ,. : : .,I ,, -_: ‘,. _. ._ .“, ...: _; ‘.. ._ ‘( .,: ” :. ._..’ : ‘:‘ ..__ .. (,‘. ‘. : ‘( ‘, : ,. ” ‘, . ,, : ,.. ‘: ,, .,’ .“‘. ,’ .,,, ,, .“, .’ ,, .,’ “,: ., ,’ .” ,‘. I, ,” _/.. ) . ,‘, . ., ., 0, ,’ ‘, ,-_ ,~ _ ,,I .. I .. : ,, :- .- ..’ : ; .“,.’ . ” ‘(’ ‘I,‘.j, .’ ‘_ ; ‘. .,: ” ._ .. ,‘ ’ ..‘, ,, ,_ ., 1: :. ..‘. .‘. ._..‘” _ : ,: ..;’ _. r. ‘,_ ._ _. _..’ ., ‘.’ ,“. ,‘, ,, (~ ‘.’ ‘, ,. .’ _,,_’ .’ : .,,, 1, _‘-’ ,,_ ;. ‘. ~ ;. ,,.’ “. 1 ,_’ .’ ,: ‘. ., “. ‘. ; _‘.(’ ,.y ,, ,, (. )I. :..; .-, ,; .,. ;’ “, .’ ,,’ :.. . ,. ._ . .., : -.. (, :_ .. .. I’ ‘,,._. , ., .. :.,. ” : ‘_ ‘.‘. ,.; (. ., _;,. ‘,” ‘. .. ” .., .‘( : ‘. .,, .” .: :.“. ,. ‘:;‘, ” ., ; .. _.‘. .., ‘. ..,’ (.’ .‘, ,I.,. -’ .: .’ : _, . ‘, ,, ‘, ‘) ; _.“_ ,‘.,‘. ‘.’ .: ., ‘. ‘: ‘. _, . ‘. ‘. ,.. -. .,.I . ,‘, ‘. ” ,’ .’ :., .’ ,.;, ,(.. ‘,,.. ‘. ;. ,.‘. ., ., : ,*I .. . . _’ ,,. ._ ._ .. . ,. __‘. ,. .; (.._ .’ ; ..‘,. ‘. ‘, ., .;, ‘., .’ _.. ” ,( ‘; (. ‘, ‘. _ ,, _. ‘~ ,, . . : ‘, ‘, . ,../ ,’ ..’ .,’ ‘., ,’ ‘, ‘. .. . _’ ” ;, ,_ ‘J : ._ ,, “. ,, ‘,,. ,_ :‘:. ‘_,‘,. (,’ ” ‘. ...‘, ,..’ ,. ._:. ,: . ‘, .( .: .‘,, .:.. ,‘,. ‘: ), ., ,, ‘. ,:’ “. ‘..‘.‘. ‘.-, : ‘. ,: .:. _’ ... ~:_:;~oluinc28, gT.$ber 4 -.. -.- : .I._ ,,‘. ‘,.
y:, .- I.’ ._:‘. :-,:, -. : ., :: :* ‘, :.