We present an in-flight fluorescence detection scheme for molecular beams which is applied to determine the enthalpy of sublimation of dye molecules. We investigate tetraphenylporphyrin (TPP), porphine, and nile red, which are believed to be suitable candidates for molecular de Broglie wave interferometry [L. Hackermüller et al., Phys. Rev. Lett. 91, 090408, 2003]. The measured values are and For TPP, sublimation enthalpies differ in the literature by more than a factor of 2. Our measurements confirm a value at the lower end of this scale. We discuss changes in the character of the molecular flow with the source temperature as a prime reason for discrepancies in the published data.
REFERENCES
1.
J. S.
Chickos
and W. E.
Acree
, J. Phys. Chem. Ref. Data
31
, 537
(2002
).2.
L. M. N. B. F.
Santos
, B.
Schröder
, O. O. P.
Fernandes
, and M. A. V.
Ribeiro da Silva
, Thermochim. Acta
415
, 15
(2004
).3.
4.
L. A.
Torres
, M.
Campos
, E.
Enrı́quez
, and R.
Patiño
, J. Chem. Thermodyn.
34
, 293
(2002
).5.
6.
7.
Atomic and Molecular Beam Methods, edited by G. Scoles (Oxford University Press, Oxford, 1988).
8.
G. A. Bird, Molecular Gas Dynamics and the Direct Simulation of Gas Flows (Clarendon, Oxford, 1994).
9.
K. D.
Carlson
, P. W.
Gilles
, and R. J.
Thorn
, J. Chem. Phys.
38
, 2725
(1963
).10.
R. A.
Mathies
, K.
Peck
, and L.
Stryer
, Anal. Chem.
62
, 1786
(1990
).11.
This is confirmed by an explicit measurement on fullerenes, which evaporate at a temperature and vapor pressure which is comparable to that of the dye molecules investigated here, but which could be detected more efficiently in laser ionization. The measured velocity distribution was a slightly shifted Boltzmann distribution.
12.
K. Hornberger, J. E. Sipe, and M. Arndt, Phys. Rev. A (to be published).
13.
D. P.
Bonderman
, E. D.
Cater
, and W. E.
Bennett
, J. Chem. Eng. Data
15
, 396
(1970
).14.
G. L.
Perlovich
, O. A.
Golubchikov
, and M. E.
Klueva
, J. Porphyrins Phthalocyanines
4
, 699
(2000
).15.
L.
Edwards
, D. H.
Dolphin
, M.
Gouterman
, and A. D.
Adler
, J. Mol. Spectrosc.
38
, 16
(1971
).16.
17.
B.
Brezger
, L.
Hackermüller
, S.
Uttenthaler
, J.
Petschinka
, M.
Arndt
, and A.
Zeilinger
, Phys. Rev. Lett.
88
, 100404
(2002
).18.
L.
Hackermüller
, S.
Uttenthaler
, K.
Hornberger
, E.
Reiger
, B.
Brezger
, A.
Zeilinger
, and M.
Arndt
, Phys. Rev. Lett.
91
, 090408
(2003
).
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