Photochemical insertion of Hg in the HCl bond and mercury-sensitized production of ClHCl - and KrHKr + in low-temperature matrices

Article abstract of DOI:10.1016/S0009-2614(99)01120-3

Using FTIR spectroscopy, we have studied the insertion reaction of Hg excited in its ³P₁ state in the HCl molecule in low-temperature Ar, Kr and N₂ matrices. A new molecule HHgCl(DHgCl) is produced. In the rare-gas matrices, we also observe the formation of ClHCl^-(ClDCl^-) and some lines which may be tentatively assigned to HgH in very perturbed sites, although they are lying far from the known absorption in the gas phase. In the Kr matrix, the absorption spectrum of Kr₂H⁺ is observed. This ion is obtained by a mercury-sensitized reaction. In argon, Ar₂H⁺ is not produced in noticeable amounts.

Full text of DOI:10.1016/S0009-2614(99)01120-3

26 November 1999
Ž
.
Chemical Physics Letters 314 1999 40–46
www.elsevier.nlrlocatercplett
Photochemical insertion of Hg in the HCl bond and
mercury-sensitized production of ClHCly and KrHKrq in
low-temperature matrices
)
N. Legay-Sommaire , F. Legay
Laboratoire de Photophysique Moleculaire, Bat. 213, UniÕersite Paris-Sud, F-91405 Orsay, France
´
ˆ
´
Received 28 July 1999; in final form 7 September 1999
Abstract
Using FTIR spectroscopy, we have studied the insertion reaction of Hg excited in its 3P1 state in the HCl molecule in
Ž
.
low-temperature Ar, Kr and N2 matrices. A new molecule HHgCl DHgCl is produced. In the rare-gas matrices, we also
y
y Ž
.
observe the formation of ClHCl ClDCl and some lines which may be tentatively assigned to HgH in very perturbed
sites, although they are lying far from the known absorption in the gas phase. In the Kr matrix, the absorption spectrum of
Kr2Hq is observed. This ion is obtained by a mercury-sensitized reaction. In argon, Ar2Hq is not produced in noticeable
amounts. q 1999 Elsevier Science B.V. All rights reserved.
1. Introduction
tion of a strong kinetic isotopic effect while the
insertion of mercury into the CH bond is much easier
than into the CD bond. In contrast for the silane
molecule, the reaction takes place without a barrier.
As the spectroscopy of HCl and its polymers was
already well known because of the exhaustive work
Reactions sensitized by mercury, in gas phase,
have been known for decades. Recent developments
of this technique have been discussed in Ref. 1 . It
is interesting to study mercuryrmolecule reactions in
matrices in order to identify the intermediate com-
pounds which are not stabilized in gas-phase reac-
tions. Therefore, for the past few years, experiments
w x
w
x
of Maillard et al. 7–10 , and because we thought
that the matrix environment is favorable, we chose
the HCl molecule to study the insertion of mercury
into a strong ionic bond. Recently using EPR spec-
have been done showing that the insertion of excited
3
w
w
x
x
w x
P1 state mercury in the hydrogen molecule 2,3 , as
troscopy, Eloranta et al. 11 studied the 193 nm
photodissociation of HCl in rare-gas matrices and
found that, of the H atoms, 6% stays in first- and
only 0.5% remains in second-neighbor positions.
Their experiments justify a posteriori our choice
because, after mercury excitation of the HCl bond,
there is a small probability that the H atom will
escape the cage, increasing the insertion probability.
well as in the CH bond of methane or ethane 4,5 , or
w x
in the SiH bond of silane 6 , is a fairly easy
Ž3
.
reaction. In methane, the insertion of Hg P1 takes
place through a small barrier, leading to the observa-
)
Corresponding author. Fax: q33-1-69156777
0009-2614r99r$ - see front matter q 1999 Elsevier Science B.V. All rights reserved.
Ž
.
PII: S0009-2614 99 01120-3

(
)
N. Legay-Sommaire, F. LegayrChemical Physics Letters 314 1999 40–46
41
Ž
In this Letter, we present new results concerning
better resolution. Hence, under high dilution
-
Ž3
.
10y3 , D 35Cl and D 37Cl absorption shows two dou-
.
the photochemistry induced by Hg P1 in the HCl
monomers and dimers giving insertion into the iso-
lated molecules and ion formation from HCl dimers.
Ž .
blets instead of two single R 0 lines as shown in
Fig. 1a for HClrDClrAr and Fig. 1c for
HClrHgrAr with DCl traces only. The observed
splitting, in argon, is 0.54 cmy1 for the two D 35Cl
Ž
lines; for HCl, the splitting is too small (0.25
2. Experimental
cmy1 to be measured and it appears as a shoulder
.
on the main line. We think that such a small splitting
is due to long-range dipole–dipole perturbations by
molecules in the second or third shell, and we only
observed the splitting in very dilute samples because,
at higher concentrations, the linewidths are larger
and the two components cannot be separated. In Fig.
1b,d, the difference spectra after irradiation are
shown; ‘b’ and ‘d’ spectra show the decrease under
irradiation of HCl and DCl intensities for two differ-
w
x
The experiments have been done as before 2–6
in our standard matrix isolation apparatus; HCl was
premixed with Ar or nitrogen and, in a few experi-
ments, with Kr. Some experiments have also been
done with a DClrHCl mixture containing about 60%
of DCl and 40% of HCl diluted in argon or nitrogen
3
matrices. The mercury was excited in the P1 state
by KrF laser emission at 249 nm. The products are
identified by their FTIR absorption spectra recorded
with a Bruker IFS 120 spectrometer. The spectra of
the samples before irradiation are used as references
and most of the spectra shown here are difference
spectra showing positive absorbance for the prod-
ucts. The vertical scales are given as an indication of
the relative intensities but the spectra are shifted for
clarity. The spectrometer is equipped with a KBr
beamsplitter and a MCT detector which allows fre-
quencies down to 600 cmy1 to be recorded with a
good signal-to-noise ratio; 525 cmy1 is the ultimate
Ž
Ž
.
Ž
.
ent samples one without a,b and one with c,d
.
mercury . They show that under KrF irradiation
Ž
.
10 000 shots without mercury only a very small
Ž
amount of HCl and DCl is dissociate perhaps due to
the presence of mercury traces . In contrast, with
.
mercury present, after only 500 laser shots a large
amount of the molecules has disappeared. This proves
that mercury is essential in the photolysis process
under 249 nm irradiation.
limit of detection. A high concentration of mercury
y3
Ž
.
ca. 10
is achieved by using a slow deposition
Ž
.
rate 3 mmolrh of the HClrAr mixture through the
stainless steel gas filter containing a drop of mer-
cury. HCl concentrations are given only as relative
indications because at 5=10y4 we cannot observe
any absorption of HCl which is adsorbed on the
walls of the stainless steel deposition device. How-
ever, at 10y3 concentration under the same condi-
tions, the absorption spectrum is fairly intense.
3. Results and discussion
3.1. Absorption spectra of HCl and DCl molecules
Ž
.
Ž
.
Ž .
Ž .
Fig. 1. HCl right and DCl left spectra at 6 K. 1 HClrDClrAr
Ž
.
Ž .
HClrHgrAr 1:;
Ž .
1:0.1:1000 without mercury: a before irradiation, b difference
Ž .
2
Ž
spectrum after 10000 KrF laser shots.
1:1000 DCl in natural abundance:
The absorption spectra of HCl and DCl have been
studied extensively; our absorption spectra are simi-
.
Ž .
c before irradiation,
d
Ž
difference spectrum after 500 KrF laser shots note the formation
ŽU ..
w
x
lar to those reported elsewhere 7–10 but we have a
of HHgCl
.

(
)
42
N. Legay-Sommaire, F. LegayrChemical Physics Letters 314 1999 40–46
Table 2
3.2. Insertion reaction of the mercury atom
y1
Ž
.
and assignments of the molecules pro-
Wavenumbers cm
duced by UV irradiation of HClrHgrAr and HClrHgrKr matri-
ces. In brackets: wavenumber of the deuterated species Cl iso-
When the HCl is highly diluted in rare gas, or
nitrogen, absorption of the HCl dimers is very small;
only two new bands are observed after UV photoly-
sis at 249 nm. These bands around 2090 and 540
Ž
.
topes
HClrHgrAr
HClrHgrKr
Assignment
ClHCly
cmy1 Tables 1 and 2 are assigned, respectively, to
the stretching and bending frequencies of the inser-
tion product HHgCl. Under a higher concentration of
1%, the spectra are shown Fig. 2 in argon and
krypton matrices.
Ž
.
695.58
662.85
n3
w
x
x
x
Ž
.
.
.
948.2 721.4
n3 qn1 37,37
w
Ž
951.7 724.6
912.1
916.0
n3 qn1 37,35
w
Ž
955.2 728.3
1193.5
n3 qn1 35,35
Ž
Ž
Ž
.
.
.
n3 q2n1 37,37
w
x
x
1200.4 975.8
n3 q2n1 37,35
This assignment is confirmed by observation of a
peak at 1500 cmy1 if HCl is replaced by DCl. This
band corresponds to the HgD stretching frequency
n3. The n2 frequency of DHgCl and the n1 Hg–Cl
stretching mode are too low to be observed in these
experiments. It should be noted that, at 1% concen-
tration, the samples show strong absorption of HCl
dimers and trimers; in this case, the intensity of all
w
1207.9 982.3
n3 q2n1 35,35
HHgCl
543.1
544.5
546.9
537.3
538.8
n2
540.8
w
x
2091.9 1500.5
2076.0
n3
Ar2 Hq
n3
902.8
Kr2 Hq
n3
n3 qn1
n3 q2n1
853.1
1009
1163
ŽŽ . .
the species HCl as well as HCl and HCl
2
.
Ž
3
decrease under irradiation, and a sharp HCl Q-branch
appears, which is not seen before irradiation because
it is forbidden. We assume that this band is induced
by some molecule produced in the reaction which
perturbs the observed one.
ment of the two lines at 2847.86 and 2845.76 cmy1
,
respectively, for 35 HCl PPP Hg and 37 HCl PPP Hg is
confirmed by the position of the corresponding lines
for DCl at 2063.0 and 2060.1 cmy1, respectively, for
3.2.1. Nitrogen matrix
In the nitrogen matrix at very low HCl concentra-
Ž
.
tion around 1:1000 , the HCl absorption line is not
too strong and it is narrow enough to allow measure-
ment of the absorption of the HCl PPP Hg complex
which is observed in the wing of the main HCl
absorption between the isolated HCl and the
highest-frequency band of the HCl dimer. Assign-
Table 1
Wavenumbers cm
y1
Ž
.
at 6 K and assignments, after irradiation of
HClrHgrN2 samples
2847.86
2845.78
2096.05
2092.16
1503.49
1500.82
2063.0
2060.1
546.7
H35ClPPPHg
H37ClPPPHg
HHgCl n3
HHgCl n3
DHgCl n3
DHgCl n3
D35ClPPPHg
D37ClPPPHg
HHgCl n2
Ž
.
Fig. 2. HHgCl spectra at 6 K after KrF irradiation of lower trace
Ž . Ž . Ž
541.1
HHgCl n2
HClrHgrAr 1:;0.1:100 and upper trace HClrHgrKr 1:;
.
0.1:100 .

(
)
N. Legay-Sommaire, F. LegayrChemical Physics Letters 314 1999 40–46
43
35 DCl PPP Hg and 37 DCl PPP Hg. Fig. 3 shows that
decrease of the intensity of the HCl PPP Hg lines,
under irradiation, is correlated with an increase of
the HHgCl absorption around 2094 cmy1. The shift
toward low frequencies for the HCl molecule in-
almost at the same position as in argon but the DCl,
Ž
.
being lower in frequency as is HCl , the intensity
measurements are easier to make in this matrix. They
show that the ratio HHgClrDHgCl is 1.4 larger than
expected from the ratio HClrDCl in the sample,
leading to the conclusion that there is probably a
small barrier to the reaction. This is confirmed by the
fact that, under 6 K irradiation after reaching a
plateau for the insertion product formation, we can
produce as much HHgCl by further irradiation at 20
K of a HClrArrHg sample with 1% HCl content.
This is not due to the migration of the species
because, at this concentration after reaching a plateau
at 6 K, the amount of HHgCl cannot be increased by
new irradiation at 6 K after 34 K annealing. This
barrier is probably orientational.
volved in a complex with the mercury atom is 7.22
y1
cmy1 4.8 cm
for DCl PPP Hg . In Fig. 3, a
Ž
.
reorganization of the main HCl band is also observed
which corresponds to a narrowing of the band; four
Ž
.
sharp peaks two strong and two smaller ones are
seen to grow as the wings of the band decrease
which shows that irradiation by the KrF laser pro-
duces a local annealing, also leading to a small
increase of HCl dimer intensity. Detection of the
absorption of the HCl PPP Hg complex has not been
possible in rare-gas matrices where the HCl lines are
much broader.
3.2.2. HHgClrDHgCl yield of formation
3.3. Formation of ions
Some experiments have been done on HClrDCl
mixtures in Ar and nitrogen matrices; unfortunately
in the Ar matrix, in concentrations large enough to
Ž
.
When the HCl DCl concentration is larger than
10y3, absorption of the HCl dimers and trimers
appears and the spectrum of the photoproducts, in
rare-gas matrices, shows new and intense bands that
are unambiguously assigned to the ClHCly ion, as
y3
Ž
.
,
measure the absorption of the products )2.10
the HHgCl band is partly overlapped by absorption
of the DCl molecule which prevents intensity mea-
surements. Thus it is impossible to compare the yield
of formation of the insertion products HHgCl and
DHgCl in argon. In nitrogen, the HHgCl band is
w
x
previously observed 12–16 . The absorption bands
of the ion are very intense compared to those of the
insertion product. In a nitrogen matrix, the ion spec-
trum is not observed and the spectrum of the inser-
tion product is the only one seen. This may be
Ž
compared to the observation of radicals SiH and
.
SiH2
produced by a two-photon process in a
SiH4rKr matrix and not in a nitrogen matrix be-
cause there is competition between the E–V transfer
3
Ž
.
from Hg P1 to the vibration of N2 and the photo-
w x
chemical reaction 6 .
The ClHCly ion has first been formed under
Ž
. w
x
VUV irradiation ca. 10 eV 13–15 ; more recently
Ž
w
x
.
Rasanen et al. Ref. 16 and references therein
¨ ¨
observed the formation of ClHCly and Ar2 Hq after
Ž
.
ArF irradiation 193 nm of an HClrAr matrix. They
identify the ions by their FTIR absorption: at 695.6
n3 and 954.9 cmy1 n3 qn1 for ClHCly and at
Ž
.
Ž
.
903 cmy1 for Ar2 Hq. In our experiments, the KrF
Ž
.
Ž
.
Fig. 3. HClrHgrN2 1:;1:1000 spectra at 6 K: HCl right and
Ž
.
Ž
.
2
HHgCl left . upper trace Spectrum before irradiation, HCl
Ž
.
Ž
.
249 nm laser is very powerful 2–15 mJrcm and
we think that formation of the ion may be a two-pho-
ton absorption process, sensitized by mercury, on
HCl dimers or trimers. It has been impossible to
absorption is truncated, C is the HCl...Hg complex, D is the
Ž
.
highest frequency band of the HCl dimer. lower trace Difference
spectrum after KrF irradiation. The dotted lines indicate the
absorption lines of the ClH...Hg complex.

(
)
44
N. Legay-Sommaire, F. LegayrChemical Physics Letters 314 1999 40–46
observe the ClHCly ion by KrF irradiation of sam-
ples containing no mercury.
different thermal behavior and their assignment is
not straightforward, although these lines are always
present when there is formation of the ion. We shall
discuss their assignment later.
In the krypton matrix, we observe the formation
of ClHCly as in argon and also the formation of the
Kr2 Hq ion. The frequencies measured for this ion
We have observed the n3, n3 qn1 and n3 q2n1
bands for ClHCly Fig. 4 which were already
known. It should be noted that the HCl used contains
35Cl and 37Cl in natural abundance and that the
isotopic shift is not seen on the n3 absorption but is
clearly seen on n3 qn1 and n3 q2n1 bands where
the three lines observed have intensities in the ratio
9:6:1 as expected for 35–35, 35–37 and 37–37
isotopes of ClHCly.
Ž
.
Ž
.
Table 2 corresponds to those observed by Rasanen
¨ ¨
w
x
et al. 16 . Fig. 5 shows the ionic species produced in
a HClrHgrKr sample after irradiation at 6 K a and
after subsequent irradiation at 25 K b . It may be
Ž .
Ž .
After 249 nm irradiation of the HClrHgrAr sam-
observed that, after 25 K irradiation, the ClHCly
integrated absorption does not decrease more than
10% in contrast to the Kr2 Hq intensities which
decrease by more than 30%. This allows confirma-
tion of the assignment of the lines to one or the other
molecular ion. The lines corresponding to the group
ples with 1% HCl, we do not observe the strong
absorption of the Ar2 Hq ion seen by Rasanen et al.
¨ ¨
w
x
16 under 193 nm irradiation. However, in highly
diluted samples, we observe it as a very small ab-
sorption at 902.8 cmy1
.
We have also observed a group of three lines
which appears around 1130 cmy1. The appearance,
but not intensities, of these lines is correlated with
that of the ClHCly ion. Hence this group of lines
cannot be assigned to ClHCly. From the literature,
the frequencies may be coincident with the n3 qn1
of the positive ion Ar2 Hq, but the intensities are not
correlated with the 903 cmy1 line intensity. How-
of lines around 1134 cmy1 in argon are observed
around 1117 cmy1. The shift 17 cm
between
y1
Ž
.
the Ar and Kr matrices is approximately the same as
the shift between the HHg stretching mode of HHgCl
in these same matrices, and this shift is much less
than that observed for the ions ClHCly or Ar2 Hq.
Furthermore, in the experiment using a HClr
DClrArrHg sample, two small lines at 850.5 and
860.8 cmy1 grow simultaneously with the 1134 and
1142 lines; these features could correspond to per-
turbed HgH and HgD molecules. It should be noted
Ž
ever, one of the three lines the main one at 1134
y1
cmy1 increases under annealing when the 903 cm
.
line decreases. The three lines in this group have
Fig. 4. Spectra at 6 K of the ClHCly ion after KrF irradiation of HClrHgrAr 1:;0.1:100 . a 10 000 laser shots 1.5 mJ , b 12 000
. Ž .
Ž
Ž
. Ž .
Ž
.
Ž
.
more shots 3 mJ ; there is no simultaneous increase of the HHgCl absorption. X see text may be HgH?

(
)
N. Legay-Sommaire, F. LegayrChemical Physics Letters 314 1999 40–46
45
qHq. In the case of 193 nm irradiation without
w
x
mercury 16 , the reaction involves two argon atoms
of the matrix and produces ClHCly and ArHArq.
Here we do not observe Ar2 Hq; hence either Ar2 Hq
dissociates under KrF irradiation in the presence of
mercury or Hq is involved in another reaction, with
mercury or HCl. The HClHq ion could be produced
from a HCl trimer, but the IR absorption of this ion
w
x
is already known 12 and is not observed here.
w
x
Lundell 18 estimates the energy necessary to
break the Ar2 Hq ion by the reaction: Ar2 Hq
ArHqqAr as 107–126 kJrmol, and Fridgen et al.
™
w
x
21 who also use a DFT calculation estimate to 69
kJrmol. The KrF laser may produce this dissocia-
tion; in this case, instead of finding Ar2 Hq, we must
find the absorption of the ArHq ion lying around
Fig. 5. Spectra at 6 K of the ClHCly and Kr2 Hq ions after KrF
. Ž .
Ž
.
Ž
10 mJ irradiation of HClrHgrKr 1:;0.1:100 : a KrF irradia-
2700 cmy1 19 . However, this is not the case and,
to our knowledge, ArHq has never been observed in
Ar matrices. Moreover, in the case of Kr2 Hq, we
observe dissociation by KrF laser irradiation at 20 K,
but no new lines are found after this dissociation,
leading to the conclusion that it dissociates into three
atoms. This seems energetically possible because
w
x
Ž .
tion at 6 K 11000 shots, b further 25 K irradiation 2700 shots. X
may be HgH?.
that these lines are observed, only in high concentra-
q
Ž
.
tion experiments 1% , where the Ar2 H lines are
absent.
What species are responsible for the small lines
observed in the 1115–1140 cmy1 region? This spec-
trum is correlated with an observation of the radicals
and thus is not observed in the nitrogen matrix. We
can rule out the HgHq molecule which is already
known and its frequency is in the 1950 cmy1 region.
It should not be due to a species containing Ar or Kr
because the shift between the group of lines in Ar
and Kr matrices is too small. From their frequency
difference and their relative intensities, we can tell
that these lines do not correspond to different Cl
isotopes, but a shift is not seen for all the vibrations
adding the KrHq dissociation energy ca. 380
Ž
q
kJrmol to the Kr2 H dissociation energy in KrHq
.
Ž
w
x
w x.
qKr 114 18 or 77 kJrmol 21 , one obtains,
respectively, 41 300 and 38 200 cmy1 compared to
y1
Ž
.
the KrF laser photon 40 300 cm . In the argon
matrix, Ar2 Hq is observed in small quantities and
only in diluted experiments, perhaps entirely dissoci-
ated by the laser; in this case, the dissociation energy
w
x
w x
calculated from Refs. 18 or 21 is always lower
than the laser photon! In their study of the photogen-
eration of ionic species in rare-gas matrices doped
Ž
w
x
of the Cl containing molecules for example n3 of
with HCl, Kunttu et al. 22 showed that thermal
ClHCly ; thus a molecule containing Cl cannot be
q
.
Ž
.
bleaching of the cation ArHAr absorption occurs
at temperatures as low as 12 K and that the kinetics
of this reaction, seen from their results, shows that
thermal bleaching is not fast enough to explain why
we see such a small absorption of the Ar2 Hq ion at
6 K.
completely ruled out. Nevertheless, the best candi-
date for these lines seems to be the HgH molecule,
but we are not sure of this assignment because there
is a strong shift towards low frequencies, compared
y1
Ž
w
x.
to the gas phase 1203 cm
17 . Such a large shift
Ž
between the gas and matrix has never been observed;
the highest shift is around 37 cmy1 for HgH2 in a
nitrogen matrix, due to a vacancy close to the
However, one problem remains: why, if true see
.
previous discussion , do we observe HgH and not
HgHq in the rare-gas matrices? Lundell and Kunttu
w x
w
x
molecule 3 .
19 in the discussion of their theoretical calculations
We assume that formation of the ClHCly ion is
found that the dissociation of Kr2 Hq into its looser
q
form Kr PPP KrH
H S , but that for Ar2 H , on the contrary, the
gives preferentially Krq2 q
Ž
.
produced by the mercury-sensitized two-photon dis-
sociation of the HCl dimer: HCl qhn ™ ClHCl
y
Ž2
.
q
Ž
.
2

(
)
46
N. Legay-Sommaire, F. LegayrChemical Physics Letters 314 1999 40–46
proton detachment is the lowest energy channel.
in gas phase but also in the low-temperature matri-
ces.
q
Ž
.
They evaluated the Rg . . . Rg–H structure to be
0.2–0.4 eV higher in energy than the symmetrical
structure. Perhaps, in our experiments, the Hg atom
being close to the Hq atom in the rare-gas matrix,
the formation of HgHqRgq2 may be favored for
some relative positions of Hg and Hq and the rare-gas
environment, after ClHCly formation? This channel
References
w x
1
R.R. Ferguson, P. Krajnik, R. Crabtree, Synlett Acc. Rapid
Ž
.
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w x
Ž
.
.
.
2
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w x
3
Ž
N. Legay-Sommaire, F. Legay, J. Phys. Chem. 99 1995
q
Ž
.
RgHRg in the Kr matrix and probably also in Ar
16945.
w x
4
Ž
because the intensity of the presumably HgH lines
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N. Legay-Sommaire, F. Legay, Chem. Phys. Lett. 217 1994
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w x
Ž .
5
w x
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.
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w x
7
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.
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w x
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Ž
.
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w x
9
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Ž
.
Phys. 71 1979 517.
w
w
w
x
10 C. Girardet, D. Maillard, A. Schriver, J.P. Perchard, J. Chem.
Ž
.
In this study, we have been able to observe for the
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x
11 J. Eloranta, K. Vaskonen, H. Kunttu, J. Chem. Phys. 110
Ž .
first time 1 the IR absorption spectrum of an IR
Ž
.
1999 7917.
Ž
.
active molecule HCl involved in a complex with
x
Ž
.
12 M.E. Jacox, J. Phys. Chem. Ref. Data. 27 1998 157 and
Ž
.
the mercury atom HCl PPP Hg complex in a nitro-
Ž .
references herein.
Ž
.
.
gen matrix, and 2 the formation of HHgCl DHgCl
w
w
w
x
Ž
Ž
.
.
13 P.N. Noble, G.C. Pimentel, J. Chem. Phys. 49 1968 3165.
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15 C.A. Wight, B.S. Ault, L. Andrews, J. Chem. Phys. 65
Ž
x
by photochemical insertion into HCl DCl of the
mercury atom pump in its P1 state by KrF excimer
3
x
Ž
.
1976 1944.
Ž
.
laser irradiation 249 nm . We have also observed
w .
16 M. Rasanen, J. Seetula, H. Kunttu, J. Chem. Phys. 98 1993
¨ ¨
x
Ž
y
q
y Ž
.
q Ž
.
formation of the ClHCl ClDCl , Kr2 H Kr2 D
3914.
and in very small amount Ar2 Hq ions, produced by
mercury-sensitized reaction. These ions have been
observed previously but they were obtained under
higher-energy irradiation or recently by electron
w
x
17 K.P. Huber, G. Herzberg Molecular Spectra and Molecular
Structure, vol. IV, Constants of Diatomic Molecules, Van
Nostrand Reinhold, New York, 1979.
w
w
w
w
w
x
Ž
.
18 J. Lundell, J. Mol. Struct. 355 1995 291.
19 J. Lundell, H. Kunttu, J. Phys. Chem. 96 1992 9774.
20 T.D. Fridgen, J.M. Parnis, J. Chem. Phys. 109 1998 2155.
21 T.D. Frigden, J.M. Parnis, J. Chem. Phys. 109 1998 2162.
x
Ž
.
w
x
bombardment of methanol in rare-gas matrices 20 .
We have thus provided a new proof that novel
mercury-sensitized reactions are occurring not only
x
Ž
Ž
.
.
x
x
Ž
.
22 H.M. Kunttu, J.A. Seetula, Chem. Phys. 189 1994 273.