Librational motion of CO in solid Ar: Raman and IR spectra and quantum simulations

Olbert‐Majkut, Adriana; Pettersson, Mika; Kiljunen, Toni

doi:10.1063/1.4739925

Cited by 7 publications

(15 citation statements)

References 43 publications

(82 reference statements)

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“…Rotational motion of isolated carbon monoxide in solid argon was considered in our previous paper 25 where we optimized the lattice structure for each orientation of the molecule with respect to crystal axes, referred as adiabatic method. Now we employ the same method with modifications when we simulate the rotational potential of isolated hydrogen and find out which effect the adding of CO in the first or second coordination shell makes to the potential.…”

Section: B Theoretical Methodsmentioning

confidence: 99%

“…Raman signal was recorded after the dissociation at 9 K and at 30 K, 20 K, and 10 K in that order, using previously described setup. 20,25 The Raman and excimer laser beams were adjusted so that the measured signal originated from the photolyzed volume. By observing the intensity change of a peak at ca.…”

Section: A Experimental Methodsmentioning

confidence: 99%

“…The CO-Ar potential 33 (Panel (b) of Fig. 1) is the same as used before in our study 25 for isolated CO, with the bond length fixed to r CO = 1.1324 Å in the potential simulation.…”

Section: Rotational Raman Spectrum Of Hmentioning

confidence: 99%

“…The measured fundamental vibrational frequency region of CO has the same spectral feature as seen before in the isolated case, i.e., when only gaseous CO is co-deposited with argon. 25 However, due to the observed band structure in the rotational spectrum of hydrogen, we have simulated the rotational motion of CO to see the possible effect of a nearby hydrogen molecule.…”

Section: Introductionmentioning

confidence: 99%

“…

Kiljunen, T. (2012). Raman spectroscopy and crystal-field split rotational states of photoproducts CO and H2 after dissociation of formaldehyde in solid argon.

…”

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confidence: 99%

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Raman spectroscopy and crystal-field split rotational states of photoproducts CO and H2 after dissociation of formaldehyde in solid argon

Olbert‐Majkut

Pettersson

Kiljunen

2012

The Journal of Chemical Physics

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Kiljunen, T. (2012). Raman spectroscopy and crystal-field split rotational states of photoproducts CO and H2 after dissociation of formaldehyde in solid argon. The Journal of Chemical Physics, 137 (16), 164310-11. doi:10.1063 Raman signal is monitored after 248 nm photodissociation of formaldehyde in solid Ar at temperatures of 9-30 K. Rotational transitions J = 2 ← 0 for para-H 2 fragments and J = 3 ← 1 for ortho-H 2 are observed as sharp peaks at 347.2 cm −1 and 578.3 cm −1 , respectively, which both are accompanied by a broader shoulder band that shows a split structure. The rovibrational spectrum of CO fragments has transitions at 2136.5 cm −1 , 2138.3 cm −1 , 2139.9 cm −1 , and 2149 cm −1 . To explain the observations, we performed adiabatic rotational potential calculations to simulate the Raman spectrum. The simulations indicate that the splitting of rotational transitions is a site effect, where H 2 molecules can reside in a substitution site, in addition to an interstitial site. In the former site, rotational motion is unperturbed by the electrostatic field of the host atoms, while the latter site splits the excited rotational manifolds, J = 2 and 3, into doublet and triplet structures, respectively. For CO, the spectrum can be ascribed to monomeric species in single-and double-substitution sites, to a dimeric species (CO) 2 , and to a CO-H 2 O complex. The simulations show that a nearest-neighbor molecular complex CO-H 2 is not responsible for any of the observed spectral fingerprints. The cause of the exit of the molecular hydrogen from the initial cage can be traced to high translational energy of the fragment after the photodissociation. After the matrix has reached a thermal equilibrium, a diffusion driven formation of the complex is possibly hindered by the high rotational zero-point energy developed upon complexation.

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Section: B Theoretical Methodsmentioning

confidence: 99%

Section: A Experimental Methodsmentioning

confidence: 99%

“…The CO-Ar potential 33 (Panel (b) of Fig. 1) is the same as used before in our study 25 for isolated CO, with the bond length fixed to r CO = 1.1324 Å in the potential simulation.…”

Section: Rotational Raman Spectrum Of Hmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…

Kiljunen, T. (2012). Raman spectroscopy and crystal-field split rotational states of photoproducts CO and H2 after dissociation of formaldehyde in solid argon.

…”

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confidence: 99%

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