Vacuum-Ultraviolet photoionization studies of the microhydrationof DNA bases (Guanine, Cytosine, Adenine and Thymine)
In this work, we report on a photoionization study of the microhydration of the four DNA bases. Gas-phase clusters of water with DNA bases [guanine (G), cytosine (C), adenine (A), and thymine (T)] are generated via thermal vaporization of the bases and expansion of the resultant vapor in a continuous supersonic jet expansion of water seeded in Ar. The resulting clusters are investigated by single-photon ionization with tunable vacuum-ultraviolet synchrotron radiation and mass analyzed using reflectron mass spectrometry. Photoionization efficiency (PIE) curves are recorded for the DNA bases and the following water (W) clusters: G, GW{sub n} (n = 1-3); C, CW{sub n} (n = 1-3); A, AW{sub n} (n = 1,2); and T, TW{sub n} (n = 1-3). Appearance energies (AE) are derived from the onset of these PIE curves (all energies in eV): G (8.1 {+-} 0.1), GW (8.0 {+-} 0.1), GW{sub 2} (8.0 {+-} 0.1), and GW{sub 3} (8.0); C (8.65 {+-} 0.05), CW (8.45 {+-} 0.05), CW{sub 2} (8.4 {+-} 0.1), and CW{sub 3} (8.3 {+-} 0.1); A (8.30 {+-} 0.05), AW (8.20 {+-} 0.05), and AW{sub 2} (8.1 {+-} 0.1); T (8.90 {+-} 0.05); and TW (8.75 {+-} 0.05), TW{sub 2} (8.6 {+-} 0.1), and TW{sub 3} (8.6 {+-} 0.1). The AEs of the DNA bases decrease slightly with the addition of water molecules (up to three) but do not converge to values found for photoinduced electron removal from DNA bases in solution.
- Research Organization:
- Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
- Sponsoring Organization:
- USDOE Director. Office of Science. Basic EnergySciences
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 928432
- Report Number(s):
- LBNL--62328; BnR: KC0301020
- Journal Information:
- Journal of Physical Chemistry A, Journal Name: Journal of Physical Chemistry A Journal Issue: 31 Vol. 111
- Country of Publication:
- United States
- Language:
- English
Similar Records
Electronic structure and spectroscopy of nucleic acid bases: Ionization energies, ionization-induced structural changes, and photoelectron spectra
Determination of ionization energies of small silicon clusters with vacuum?ultraviolet (VUV) radiation