Two-photon, two-color double-resonance ionization spectroscopy combining synchrotron vacuum ultraviolet radiation with a tunable near-infrared (NIR) laser has been used to investigate gerade symmetry states of the nitrogen molecule. The rotationally resolved spectrum of an autoionizing (1)Sigma(-)(g) state has been excited via the intermediate c(4) (v = 0) (1)Pi(u) Rydberg state. We present the analysis of the band located at T-v = 10 800.7 +/- 2 cm(-1) with respect to the intermediate state, 126 366 +/- 11 cm(-1) with respect to the ground state, approximately 700 cm(-1) above the first ionization threshold. From the analysis a rotational constant of B-v = 1.700 +/- 0.005 cm(-1) has been determined for this band. Making use of the pulsed structure of the two radiation beams, lifetimes of several rotational levels of the intermediate state have been measured. We also report rotationally-averaged fluorescence lifetimes (300 K) of several excited electronic states accessible from the ground state by absorption of one photon in the range of 13.85-14.9 eV. The averaged lifetimes of the c(4) (0) and c(5) (0) states are 5.6 and 4.4 ns, respectively, while the b' (12), c(4)' (4, 5, 6), and c(5)' (0) states all have lifetimes in the range of hundreds of picoseconds. (C) 2011 American Institute of Physics. [doi:10.1063/1.3560909]
Time-resolved study of excited states of N-2 near its first ionization threshold
2011
Abstract
Two-photon, two-color double-resonance ionization spectroscopy combining synchrotron vacuum ultraviolet radiation with a tunable near-infrared (NIR) laser has been used to investigate gerade symmetry states of the nitrogen molecule. The rotationally resolved spectrum of an autoionizing (1)Sigma(-)(g) state has been excited via the intermediate c(4) (v = 0) (1)Pi(u) Rydberg state. We present the analysis of the band located at T-v = 10 800.7 +/- 2 cm(-1) with respect to the intermediate state, 126 366 +/- 11 cm(-1) with respect to the ground state, approximately 700 cm(-1) above the first ionization threshold. From the analysis a rotational constant of B-v = 1.700 +/- 0.005 cm(-1) has been determined for this band. Making use of the pulsed structure of the two radiation beams, lifetimes of several rotational levels of the intermediate state have been measured. We also report rotationally-averaged fluorescence lifetimes (300 K) of several excited electronic states accessible from the ground state by absorption of one photon in the range of 13.85-14.9 eV. The averaged lifetimes of the c(4) (0) and c(5) (0) states are 5.6 and 4.4 ns, respectively, while the b' (12), c(4)' (4, 5, 6), and c(5)' (0) states all have lifetimes in the range of hundreds of picoseconds. (C) 2011 American Institute of Physics. [doi:10.1063/1.3560909]I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
