We study the infrared (IR) resonant heating of neutral niobium carbide clusters probed through ultraviolet photoionization spectroscopy. The IR excitation not only changes the photoionization spectra for the photon energies above the ionization threshold, but also modulates ion yield for energies significantly below it. An attempt to describe the experimental spectra using either Fowler’s theory or thermally populated vibrational states was not successful. However, the data can be fully modeled by vibrationally and rotationally broadened discrete electronic levels obtained from Density Functional Theory (DFT) calculations. The application of this method to spectra with different IR pulse energies not only yields information about the excited electronic states in the vicinity of the HOMO level, populated by manipulation of the vibrational coordinates of a cluster, but also can serve as an extra indicator for the cluster isomeric structure and corresponding DFT-calculated electronic levels.

1.
N.
Ashcroft
and
N.
Mermin
,
Solid State Physics
(
Saunders College
,
Philadelphia
,
1976
).
2.
W.
Domcke
,
D. R.
Yarkony
, and
H.
Koppel
,
Conical Intersections
(
World Scientific Publishing Co. Pte. Ltd.
,
Singapore
,
2011
).
3.
E.
Cappelluti
and
L.
Pietronero
, “
Electron-phonon renormalization in small fermi energy systems
,”
Phys. Rev. B
68
,
224511
(
2003
).
4.
A. K.
Geim
and
K. S.
Novoselov
, “
The rise of graphene
,”
Nat. Mater.
6
,
198
(
2007
).
5.
S.
Yang
and
M. B.
Knickelbein
, “
Photoionization studies of transition metal clusters: Ionization potentials of ScnO (n = 5-36)
,”
J. Chem. Phys.
93
,
1533
(
1990
).
6.
W. A.
de Heer
, “
The physics of simple metal clusters: Experimental aspects and simple models
,”
Rev. Mod. Phys.
65
,
611
(
1993
).
7.
H.
Hohmann
,
C.
Callegari
,
S.
Furrer
,
D.
Grosenick
,
E. E. B.
Campbell
, and
I. V.
Hertel
, “
Photoionization and fragmentation dynamics of C60
,”
Phys. Rev. Lett.
73
,
1919
(
1994
).
8.
E. E. B.
Campbell
,
G.
Ulmer
, and
I. V.
Hertel
, “
Delayed ionization of C60 and C70
,”
Phys. Rev. Lett.
67
,
1986
(
1991
).
9.
K.
Hansen
,
J. U.
Andersen
,
P.
Hvelplund
,
S. P.
Møller
,
U. V.
Pedersen
, and
V. V.
Petrunin
, “
Observation of a 1/t decay law for hot clusters and molecules in a storage ring
,”
Phys. Rev. Lett.
87
,
123401
(
2001
).
10.
B.
Baguenard
,
J. C.
Pinare
,
C.
Bordas
, and
M.
Broyer
, “
Photoelectron imaging spectroscopy of small tungsten clusters: Direct observation of thermionic emission
,”
Phys. Rev. A
63
,
023204
(
2001
).
11.
E. E. B.
Campbell
and
R. D.
Levine
, “
Delayed ionization and fragmentation en route to thermionic emission: Statistics and dynamics
,”
Annu. Rev. Phys. Chem.
51
,
65
(
2000
).
12.
J. U.
Andersen
,
E.
Bonderup
, and
K.
Hansen
, “
Thermionic emission from clusters
,”
J. Phys. B: At., Mol. Opt. Phys.
51
,
R1
(
2002
).
13.
M.
Maier
,
G.
Wrigge
,
M. A.
Hoffmann
,
P.
Didier
, and
B. v.
Issendorff
, “
Observation of electron gas cooling in free sodium clusters
,”
Phys. Rev. Lett.
96
,
117405
(
2006
).
14.
D.
van Heijnsbergen
,
G.
von Helden
,
M. A.
Duncan
,
A. J. A.
van Roij
, and
G.
Meijer
, “
Vibrational spectroscopy of gas-phase metal-carbide clusters and nanocrystals
,”
Phys. Rev. Lett.
83
,
4983
(
1999
).
15.
G.
von Helden
,
I.
Holleman
,
G. M. H.
Knippels
,
A. F. G.
van der Meer
, and
G.
Meijer
, “
Infrared resonance enhanced multiphoton ionization of fullerenes
,”
Phys. Rev. Lett.
79
,
5234
(
1997
).
16.
J.
Jalink
,
J. M.
Bakker
,
T.
Rasing
, and
A.
Kirilyuk
, “
Channeling vibrational energy to probe the electronic density of states in metal clusters
,”
J. Phys. Chem. Lett.
6
,
750
754
(
2015
).
17.
G.
von Helden
,
I.
Holleman
,
M.
Putter
,
A.
van Roij
, and
G.
Meijer
, “
Infrared resonance enhanced multi-photon ionization spectroscopy of C84
,”
Chem. Phys. Lett.
299
,
171
176
(
1999
).
18.
A.
Fielicke
,
J. T.
Lyon
,
M.
Haertelt
,
G.
Meijer
,
P.
Claes
,
J.
de Haeck
, and
P.
Lievens
, “
Vibrational spectroscopy of neutral silicon clusters via far-IR-VUV two color ionization
,”
J. Chem. Phys.
131
,
171105
(
2009
).
19.
D.
Oepts
,
A. F. G.
van der Meer
, and
P. W.
van Amersfoort
, “
The free-electron-laser user facility FELIX
,”
Infrared Phys. Technol.
36
,
297
308
(
1995
).
20.
G.
Kresse
and
J.
Furthmüller
, “
Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set
,”
Phys. Rev. B
54
,
11169
11186
(
1996
).
21.
P. E.
Blöchl
, “
Projector augmented-wave method
,”
Phys. Rev. B
50
,
17953
17979
(
1994
).
22.
G.
Kresse
, “
From ultrasoft pseudopotentials to the projector augmented-wave method
,”
Phys. Rev. B
59
,
1758
1775
(
1999
).
23.
J. P.
Perdew
and
Burke
, “
Generalized gradient approximation made simple
,”
Phys. Rev. Lett.
77
,
3865
3868
(
1996
).
24.
R. L.
Johnston
, “
Evolving better nanoparticles: Genetic algorithms for optimising cluster geometries
,”
Dalton Trans.
4193
(
2003
).
25.
R.
Logemann
,
G. A.
de Wijs
,
M. I.
Katsnelson
, and
A.
Kirilyuk
, “
Geometric, electronic, and magnetic structure of Fe x O y + clusters
,”
Phys. Rev. B
92
,
144427
(
2015
).
26.
N.
Fukushima
,
K.
Miyajima
, and
F.
Mafuné
, “
Ionization energies of niobium carbide clusters NbnCm (n = 3-10, m = 0-7)
,”
J. Phys. Chem. A
113
,
2309
2315
(
2009
).
27.
D.
van Heijnsbergen
,
A.
Fielicke
,
G.
Meijer
, and
G.
von Helden
, “
Structure determination of gas-phase niobium and tantalum carbide nanocrystals via infrared spectroscopy
,”
Phys. Rev. Lett.
89
,
013401
(
2002
).
28.
D.-S.
Yang
,
M. Z.
Zgierski
,
A.
Berces
,
P. A.
Hackett
,
P.-N.
Roy
,
A.
Martinez
,
J. T.
Carrington
,
D. R.
Salahub
,
R.
Fournier
,
T.
Pang
, and
C.
Chen
, “
Vibrational and geometric structures of Nb3C2 and Nb 3 C 2 + from pulsed field ionization-zero electron kinetic energy photoelectron spectra and density functional calculations
,”
J. Chem. Phys.
105
,
10663
10671
(
1996
).
29.
M. B.
Knickelbein
and
S.
Yang
, “
Photoionization and fragmentation dynamics of C60
,”
J. Chem. Phys.
93
,
5760
5767
(
1990
).
30.
R.
Fowler
, “
Photoelectric sensitivity
,”
Phys. Rev.
38
,
107
(
1931
).
31.
A.
Prem
and
V. V.
Kresin
, “
Photoionization profiles of metal clusters and the Fowler formula
,”
Phys. Rev. A
85
,
8
11
(
2012
).
32.
M.
Putter
,
G.
von Helden
, and
G.
Meijer
, “
Mass selective infrared spectroscopy using a free electron laser
,”
Chem. Phys. Lett.
258
,
118
122
(
1996
).
33.
J.
Oomens
,
B. G.
Sartakov
,
G.
Meijer
, and
G.
von Helden
, “
Gas-phase infrared multiple photon dissociation spectroscopy of mass-selected molecular ions
,”
Int. J. Mass Spectrom.
254
,
1
19
(
2006
).
34.
S. E.
Stein
and
B. S.
Rabinovitch
, “
Accurate evaluation of internal energy level sums and densities including anharmonic oscillators and hindered rotors
,”
J. Chem. Phys.
58
,
2438
(
1973
).
35.
H. G.
Limberger
and
T. P.
Martin
, “
Ionization energies of cesium and cesium oxide clusters
,”
J. Chem. Phys.
90
,
2979
(
1989
).
36.
T.
Bergmann
and
T. P.
Martin
, “
Observation of electronic shell structure in large cesium oxide clusters
,”
J. Chem. Phys.
90
,
2848
(
1989
).
37.
V.
Dryza
,
M. A.
Addicoat
,
J. R.
Gascooke
,
M. A.
Buntine
, and
G. F.
Metha
, “
Threshold photoionization and density functional theory studies of the niobium carbide clusters Nb3Cn (n = 1-4) and Nb4Cn, (n = 1-6)
,”
J. Phys. Chem. A
112
,
5582
5592
(
2008
).
38.
K.
Hansen
,
Statistical Physics of Nanoparticles in the Gas Phase
(
Springer
,
The Netherlands
,
2013
).
39.
J. M.
Bakker
,
V. J. F.
Lapoutre
,
B.
Redlich
,
J.
Oomens
,
B. G.
Sartakov
,
A.
Fielicke
,
G.
von Helden
,
G.
Meijer
, and
A. F. G.
van der Meer
, “
Intensity-resolved IR multiple photon ionization and fragmentation of C60
,”
J. Chem. Phys.
132
,
1
9
(
2010
).
40.
F.
Calvo
,
Y.
Li
,
D. M.
Kiawi
,
J. M.
Bakker
,
P.
Parneix
, and
E.
Janssens
, “
Nonlinear effects in infrared action spectroscopy: Experiment and kinetic modeling
,”
Phys. Chem. Chem. Phys.
17
,
25956
25967
(
2015
).
You do not currently have access to this content.