Multiphoton Ionization/Dissociation of Molecular Sulfur S2 in the UV Region.

The multiphoton ionization/dissociation dynamics of molecular sulfur (S2) in the ultraviolet range of 205-300 nm is studied using velocity map ion imaging (VMI). In this one-color experiment, molecular sulfur (S2) is generated in a pulsed discharge and then photodissociated by UV radiation. At the three-photon level, superexcited states are accessed via two different resonant states: the B3Σu- (v' = 8-11) valence states at the one-photon level and a Rydberg state at the two-photon level. Among the decay processes of these superexcited states, dissociation to electronically excited S atoms is dominant as compared to autoionization to ionic states S2+ (X2Πg) at wavelengths λ < 288 nm. The anisotropy parameter extracted from these images reflects the parallel character of these electronic transitions. In contrast, autoionization is found to be particularly efficient at S(1D) and S(1S) detection wavelengths around 288 nm. Information obtained from the kinetic energy distributions of S atoms has revealed the existence of vibrationally excited S2+ (X2Πg (v+ > 11)) that dissociates to ionic products following one-photon absorption. This work also reveals many interesting features of S2 photodynamics compared to those of electronically analogous O2.

Photoionization cross sections measurements of the excited states of lutetium and ytterbium in the near threshold region.

In this work, the threshold photoionization cross sections from the excited states of lutetium and ytterbium atoms were investigated by the laser pump-probe scheme under the condition of saturated resonant excitation. We obtained the resonance enhanced multiphoton ionization spectra of the lutetium and ytterbium atoms of the lanthanide metals in the range of 307.50-312.50 nm and 265.00-269.00 nm, respectively; the photoionization cross sections of the 5d6s(1D)6p(2D05/2) and 5d6s(3D)6p(2P01/2) states of lutetium and the 4f13(2F0)5d6s2(J = 1) states of ytterbium above threshold regions (0.4-1.6 eV) were measured, and measured values ranged from 2.3 ± 0.2 to 17.7 ± 1.5 Mb.

Detection of trace phosphorus in water by plasma amplification laser-induced breakdown spectroscopy.

For monitoring the extent of eutrophication in water, phosphorus (P) was detected by laser-induced breakdown spectroscopy (LIBS). A plasma amplification method was proposed and the filtered aerosol was guided to interact with the collinear laser in conjunction with a nebulizer, cyclonic spray chamber, and quartz tube. With this method, the length of the plasma was amplified from 5.27∼8.73 to 17.58 mm. Moreover, the limit of detection (LoD) values of P in water improved from 6.13∼17.75 to 3.60 ppm. Furthermore, the average relative error (REAV) values reduced from 10.23∼23.84 to 6.17%. The root mean square error of cross-validation (RMSECV) values decreased from 16.68∼64.29 to 3.24 ppm. This demonstrated that plasma amplification LIBS could improve the quantitative analysis performance of LIBS detection of trace phosphorus in water.

Predissociation dynamics of the A2Σ+ state of SH radical: Fine-structure state distributions of the S(3PJ) products.

Photo-predissociation of rovibrational levels of SH (A2Σ+, v' = 0-6) is studied using the high-n Rydberg atom time-of-flight technique. Spin-orbit branching fractions of the S(3PJ=2,1,0) products are measured in the product translational energy distributions. The SH A2Σ+v' = 0 state predissociates predominantly via coupling to the 4Σ- repulsive state. As the vibrational level v' increases, predissociation dynamics change drastically, with all three repulsive states (4Σ-, 2Σ-, and 4Π) involved in the dissociation. Nonadiabatic interactions and quantum interferences among these dissociation pathways affect the fine-structure state distributions of the S(3PJ=2,1,0) products.

Photodissociation dynamics of the ethyl radical via the Ã2A'(3s) state: H-atom product channels and ethylene product vibrational state distribution.

The photodissociation dynamics of jet-cooled ethyl radical (C2H5) via the Ã2A'(3s) states are studied in the wavelength region of 230-260 nm using the high-n Rydberg H-atom time-of-flight (TOF) technique. The H + C2H4 product channels are reexamined using the H-atom TOF spectra and photofragment translational spectroscopy. A prompt H + C2H4(X̃1Ag) product channel is characterized by a repulsive translational energy release, anisotropic product angular distribution, and partially resolved vibrational state distribution of the C2H4(X̃1Ag) product. This fast dissociation is initiated from the 3s Rydberg state and proceeds via a H-bridged configuration directly to the H + C2H4(X̃1Ag) products. A statistical-like H + C2H4(X̃1Ag) product channel via unimolecular dissociation of the hot electronic ground-state ethyl (X̃2A') after internal conversion from the 3s Rydberg state is also examined, showing a modest translational energy release and isotropic angular distribution. An adiabatic H + excited triplet C2H4(ã3B1u) product channel (a minor channel) is identified by energy-dependent product angular distribution, showing a small translational energy release, anisotropic angular distribution, and significant internal excitation in the C2H4(ã3B1u) product. The dissociation times of the different product channels are evaluated using energy-dependent product angular distribution and pump-probe delay measurements. The prompt H + C2H4(X̃1Ag) product channel has a dissociation time scale of <10 ps, and the upper bound of the dissociation time scale of the statistical-like H + C2H4(X̃1Ag) product channel is <5 ns.

Distributed Partial Discharge Locating and Detecting Scheme Based on Optical Fiber Rayleigh Backscattering Light Interference.

Optical fiber sensors are used for partial discharge detection in many applications due their advantage of strong anti-electromagnetic interference capability. Multi-point distributed partial discharge detection and location are important for electrical equipment. In this paper, a distributed partial discharge location and detection scheme based on optical fiber Rayleigh backscattering light interference is experimentally demonstrated. At the same time, the location and extraction algorithm is used to demodulate the partial discharge signal; furthermore, the high-pass filter is used to reduce the system low-frequency noise and environment noise. It is clear that the proposed system can detect a partial discharge signal generated by metal needle sensitivity, and the detectable frequency range is 0-2.5 kHz. We carried out 10 locating tests for two sensing units, the experimental results show that the maximum location error is 1.0 m, and the maximum standard deviation is 0.3795. At same time, the signal-to-noise ratio (SNR) of sensing unit 1 and sensing unit 2 are greatly improved after demodulation, which are 39.7 and 38.8, respectively. This provides a new method for a multipoint-distributed optical fiber sensor used for detecting and locating a long-distance electrical equipment partial discharge signal.

Properties of Gaseous Deprotonated L-Cysteine S-Sulfate Anion [cysS-SO3]-: Intramolecular H-Bond Network, Electron Affinity, Chemically Active Site, and Vibrational Fingerprints.

L-cysteine S-sulfate, Cys-SSO3H, and their derivatives play essential roles in biological chemistry and pharmaceutical synthesis, yet their intrinsic molecular properties have not been studied to date. In this contribution, the deprotonated anion [cysS-SO3]- was introduced in the gas phase by electrospray and characterized by size-selected, cryogenic, negative ion photoelectron spectroscopy. The electron affinity of the [cysS-SO3]• radical was determined to be 4.95 ± 0.10 eV. In combination with theoretical calculations, it was found that the most stable structure of [cysS-SO3]- (S1) is stabilized via three intramolecular hydrogen bonds (HBs); i.e., one O-H⋯⋯N between the -COOH and -NH2 groups, and two N-H⋯⋯O HBs between -NH2 and -SO3, in which the amino group serves as both HB acceptor and donor. In addition, a nearly iso-energetic conformer (S2) with the formation of an O-H⋯⋯N-H⋯⋯O-S chain-type binding motif competes with S1 in the source. The most reactive site of the molecule susceptible for electrophilic attacks is the linkage S atom. Theoretically predicted infrared spectra indicate that O-H and N-H stretching modes are the fingerprint region (2800 to 3600 cm-1) to distinguish different isomers. The obtained information lays out a foundation to better understand the transformation and structure-reactivity correlation of Cys-SSO3H in biologic settings.

Unimolecular dissociation dynamics of electronically excited HCO(Ã2A''): rotational control of nonadiabatic decay.

The photoinduced unimolecular decay of the electronically excited HCO(Ã2A'') is investigated in a combined experimental-theoretical study. The molecule is excited to the (1, n2, 0) combination bands, which decay via Renner-Teller coupling to the ground electronic state. The rovibrational state distribution of the CO fragment was measured via the high-n Rydberg H-atom time-of-flight method and calculated using a wave packet method on an accurate set of potential energy surfaces. It is shown that the non-adiabatic decay rate is strongly modulated by the HCO rotational angular momentum, which leaves unique signatures in the product state distribution. The experimentally observed bimodal rotational distribution of the dominant CO(v = 0) fragment is likely due to decay of different vibronic states populated by the excitation and modulated by the excited state lifetime, which is in turn controlled by the parent rotational quantum number.

Two-photon dissociation dynamics of the mercapto radical.

Two-photon dissociation dynamics of the SH/SD radicals are investigated using the high-n Rydberg atom time-of-flight (HRTOF) technique. The H/D(2S) + S(1D) and H/D(2S) + S(1S) products are observed in the dissociation of the SH/SD radicals on the 22Π and B2Σ+ repulsive states, from sequential two-photon excitation via the A2Σ+ (v' = 0, J' = 0.5-2.5) state. The angular distributions of both H/D(2S) + S(1D) and H/D(2S) + S(1S) product channels are anisotropic. The anisotropy parameter (ß) of the H(2S) + S(1D) products is ∼-0.8 ± 0.1 (-0.9 ± 0.05 for SD), and that of the H(2S) + S(1S) products is ∼1.3 ± 0.3 (1.2 for SD). The anisotropic angular distributions indicate that the SH/SD radicals promptly dissociate on the repulsive 22Π and B2Σ+ potential energy curves (PECs) along with some non-adiabatic crossings, leading to the H/D(2S) + S(1D) and H/D(2S) + S(1S) products, respectively. The bond dissociation energy of the ground-state X2Π3/2 SH/SD to the ground-state H/D(2S) + S(3P2) products is measured to be D0(S-H) = 29 253 ± 20 cm-1 and D0(S-D) = 29 650 ± 20 cm-1, respectively. The dissociation energy of the A2Σ+ state SH/SD to the H/D(2S) + S(1D) products is derived to be D0[S-H(A)] = 7659 ± 20 cm-1 and D0[S-D(A)] = 7940 ± 20 cm-1.

Vibrational energy levels and predissociation lifetimes of the A2Σ+ state of SH/SD radicals by photodissociation spectroscopy.

Photo-predissociation of SH and SD radicals in the A2Σ+ state is investigated using the high-n Rydberg atom time-of-flight technique. By measuring the photoproduct translational energy distributions as a function of excitation wavelength, contributions from overlapping A2Σ+ (v') ← X2Π (v″) transitions can be separated, and the H/D + S(3PJ) photofragment yield (PFY) spectra are obtained across various rovibrational levels (SH v' = 0-7 and SD v' = 0-8) of the A2Σ+ ← X2Π bands. The upper A2Σ+ state vibrational levels v' = 5-7 of SH and v' = 3-8 of SD are determined for the first time. The PFY spectra are analyzed with the simulation program PGOPHER [C. M. Western, J. Quant. Spectrosc. Radiat. Transfer 186, 221 (2016)], which gives vibrational origins and linewidths of the rovibrational levels of the A2Σ+ state. The linewidths (≥1.5 cm-1) of the SH A2Σ+ v' = 3-7 and SD A2Σ+ v' = 2-8 states are characterized for the first time in this work, demonstrating that these levels undergo rapid predissociation with lifetimes on the order of picosecond. The lifetimes of the SD A2Σ+ v' = 0, N' = 1 and 2 levels are determined to be 247 ± 50 ns and 176 ± 60 ns by pump-probe delay measurements, respectively. The experimentally measured lifetimes are in reasonable agreement with the theoretical predictions.

Photodissociation Dynamics of Vinoxy Radical via the B̃2A″ State: The H + CH2CO Product Channel.

Photodissociation dynamics of the jet-cooled vinoxy radical (CH2CHO) via the B̃2A″ state was studied in the near-ultraviolet (near-UV) region of 308-328 nm using high-n Rydberg H atom time-of-flight (HRTOF) and resonance-enhanced multiphoton ionization (REMPI) techniques. The vinoxy radical beam was produced by 193 nm photolysis of ethyl vinyl ether followed by supersonic expansion. The H + CH2CO product channel was observed directly in the H atom TOF spectra. The H atom photofragment yield (PFY) spectra were obtained by integrating the H atom TOF spectra and measuring the H atom REMPI signals, and showed several vibronic bands of the B̃2A″ state. The translational energy distributions of the H + CH2CO products, P(ET)'s, were obtained at several vibronic transitions. The P(ET) distributions were broad, peaking at a low energy of ∼3500 cm-1. The product translational energy release was moderate; the average translational energy release in the maximum available energy, ⟨fT⟩, was in the range of 0.24-0.27. The product angular distributions in this wavelength region were slightly anisotropic, with the ß parameter in the range of 0.10-0.24. The near-UV photodissociation mechanism of the H + CH2CO product channel of the vinoxy radical is consistent with unimolecular dissociation on the electronic ground state (X̃2A″) following internal conversion from the B̃2A″ state to the Ã2A' state and then to the X̃2A″ state (although unimolecular dissociation from the first excited Ã2A' may also contribute).

Quantitative insights into non-uniform plasmonic hotspots due to symmetry breaking induced by oblique incidence.

Localized surface plasmon resonance draws great attentions mainly due to its enhanced near electric field, i.e., plasmonic hotspots. The symmetry breaking via oblique incidence of light is predicted to influence the intensity of plasmonic hotspots. However, relevant experimental investigation in quantitative comparison with theory is still lacking. Here, we visualize the polarization-dependent plasmonic hotspots of a triangular Ag nanoplate through oblique-incidence photoemission electron microscopy (PEEM), revealing a non-uniform near-field enhancement. Under oblique incidence, two bright spots and one dark spot were identified in the polarization-averaged PEEM image, different from that for normal illumination where bright spots with equal intensity are anticipated. In polarization-dependent PEEM images, plasmonic hotspots appeared at specific corners of a triangular Ag nanoplate, and rotated in a manner consistent with the rotation of polarization angle. The experimental intensity maps of the photoelectron were well reproduced by simulation on a quantitative level. This work provides a quantitative understanding of how the orientation of incidence light relative to a plasmonic antenna influences the near-field enhancement.

Ultraviolet photodissociation dynamics of the n-butyl, s-butyl, and t-butyl radicals.

Photodissociation dynamics of the jet-cooled n-butyl radical via the 3s Rydberg state and the s-butyl radical via the 3p Rydberg states in the ultraviolet region of 233 nm-258 nm, as well as the t-butyl radical via the 3d Rydberg states at 226 nm-244 nm, are studied using the high-n Rydberg atom time-of-flight technique. The H-atom photofragment yield spectra of the n-butyl, s-butyl, and t-butyl radicals show a broad feature centered around 247 nm, 244 nm, and 234 nm, respectively. The translational energy distributions of the H + C4H8 products, P(ET)'s, of the three radicals are bimodal, with a slow (low ET) component peaking at ∼6 kcal/mol and a fast (high ET) component peaking at ∼52 kcal/mol-57 kcal/mol, ∼43 kcal/mol, and ∼37 kcal/mol for n-butyl, s-butyl, and t-butyl, respectively. The fraction of the products' translational energy in the available energy, ⟨ fT⟩, is 0.31, 0.30, and 0.27 for n-butyl, s-butyl, and t-butyl, respectively. The H-atom product angular distributions of the slow component are isotropic for all three radicals, while those of the fast component are anisotropic for n-butyl and s-butyl with an anisotropy parameter ß âˆ¼ 0.7 and ∼ 0.3 and that of the fast component of t-butyl is nearly isotropic. The bimodal product translational energy and angular distributions indicate two dissociation pathways to the H + C4H8 products in these three radicals, a direct, prompt dissociation on the repulsive potential energy surface coupling with the Rydberg excited states, and a unimolecular dissociation of the hot radical on the ground electronic state after internal conversion from the Rydberg states.

H-Atom Product Channel in the Ultraviolet Photodissociation of the Thiomethoxy Radical (CH3S) via the B̃2A2 State.

The photodissociation dynamics of jet-cooled thiomethoxy radical (CH3S) via the B̃2A2 ← X̃2E transition was studied in the ultraviolet region of 216-225 nm using the high-n Rydberg H-atom time-of-flight (HRTOF) technique. The H-atom product channel was directly observed from the H-atom TOF spectra (using both dimethyl disulfide and dimethyl sulfide precursors). The H-atom photofragment yield spectrum showed a broad feature in the region of 216-225 nm and three B̃2A2 vibronic peaks at 217.7, 220.3, and 221.5 nm. Several H-atom dissociation pathways were identified. The excited-state CH3S had a repulsive, prompt dissociation pathway to the ground-state H2CS(X̃1A1) + H products, with the product translational energy peaking near the maximum available energy, a predominant C-S stretch vibrational excitation in H2CS(X̃1A1), and an anisotropic angular distribution. The main pathway was the H2CS(X̃1A1) + H product channel via the unimolecular dissociation of internally hot CH3S radical in the ground electronic state after internal conversion from the electronic excited state, with a modest translational energy release (peaking at a low translational energy of ∼11 kcal/mol and extending near the maximum available energy) and a nearly isotropic angular distribution. The H + H2CS(Ã1A2) and H + H2CS(ã3A2) product channels were also observed but were minor channels. The C-H bond dissociation energy of CH3S to the H + H2CS(X̃1A1) products was determined to be 48.8 ± 0.7 kcal/mol.

Spectroscopic identification of the low-lying electronic states of S2 molecule.

As is well-known, the S2 molecule is a ubiquitous intermediate in the combustion, atmosphere, and interstellar space. The six low-lying bound states of S2 have been characterized via photoelectron velocity map imaging and a high-level multi-reference configuration interaction method with the Davidson correction. Spectroscopic constants have been extracted by fitting the potential energy curves extrapolated to the complete basis set limit with a series of Dunning's correlation-consistent basis sets: aug-cc-pV(Q, 5)Z. The calculated spectroscopic parameters well reproduce the experimental results in this work. On the basis of the theoretical calculations, Franck-Condon simulations are performed to assign six adjacent electronic states, especially for three higher overlapping electronic states (c1Σu -, A'3Δu, and A3Σu +). The dissociation energy De of the S2 - is evaluated to be 4.111 (4) eV in this work, in agreement with the theoretical prediction (4.056 eV).

Left ventricular systolic dysfunction potentially contributes to the symptoms in heart failure with preserved ejection fraction.

AIMS: Left ventricular diastolic dysfunction (LVDD) is considered a key factor associated with heart failure (HF) symptoms in patients with preserved ejection fraction (HFpEF). However, LV systolic performance, including LV systolic function and synchrony, has not been well characterized in these patients. The aims of this study were to assess to investigate the underlying relationship and differences between subclinical LVDD and HFpEF. METHODS: Eighty-six patients with LVDD were recruited (58 with HFpEF and 28 with subclinical LVDD). Systolic left ventricular (LV) longitudinal strain (LS), systolic longitudinal strain rate (LSrS), early diastolic longitudinal strain rate (LSrE), and late diastolic longitudinal strain rate (LSrA) were measured using speckle tracking echocardiography. LV diastolic and systolic dyssynchrony (Te-SD and Ts-SD) were calculated. Forty age- and sex-matched healthy individuals were enrolled as a control group. RESULTS: LV global LS and LSrS were decreased in patients with HFpEF than in normal controls and subclinical LVDD patients (P < .05). Te-SD and Ts-SD were significantly more prolonged in subclinical LVDD and HFpEF patients than in the control group (P < .05). Reduced LS was associated with HF symptoms in LVDD patients, and a cutoff value of -18% for LS could differentiate HFpEF from subclinical LVDD with 73% sensitivity and 69% specificity. CONCLUSION: LV systolic function and mechanical dyssynchrony were impaired in HFpEF patients. Deteriorated LV longitudinal systolic function was likely correlated with the symptoms of HFpEF.

Left ventricular diastolic and systolic dyssynchrony and dysfunction in heart failure with preserved ejection fraction and a narrow QRS complex.

Aims: Mechanical dyssynchrony has been reported in heart failure with preserved ejection fraction (HFpEF), with a majority of patients having a narrow QRS complex; however, whether any benefit is observed with restoration of dyssynchrony remains unclear. We sought to assess left ventricular (LV) dyssynchrony and function in HFpEF and elucidate the underlying mechanisms that may account for HFpEF. Methods: Seventy-eighty patients with a narrow QRS complex including 47 with HFpEF, 31 with heart failure with reduced ejection fraction (HFrEF) patients, and 29 with asymptomatic left ventricular diastolic dysfunction (LVDD) were recruited. Forty-five normal subjects acted as controls. Systolic LV longitudinal strain (LS), systolic longitudinal strain rate (LSrS), early diastolic longitudinal strain rate (LSrE), and late diastolic longitudinal strain rate (LSrA) were measured using speckle tracking echocardiography. LV diastolic and systolic dyssynchrony (Te-SD and Ts-SD) were calculated. Results: Te-SD and Ts-SD were prolonged in HFpEF and HFrEF patients than in the control group (p<0.05). However, Ts-SD was shorter in HFpEF patients compared to HFrEF patients despite a narrow QRS complex (p<0.05). LV global LS, LSrS, and LSrE were decreased in patients with HFpEF and HFrEF compared to other groups, with HFrEF being even more reduced than HFpEF (p<0.05). Reduced LS, LSrS, and LSrE could effectively differentiate HF from asymptomatic LVDD patients (p<0.05). Conclusion: HFrEF exhibited increased systolic dyssynchrony compared to HFpEF despite a narrow QRS complex in addition to the more reduced diastolic and systolic function. Therefore, targeting to improve diastolic and systolic function instead of managing systolic dyssynchrony might be of great importance in the treatment of HFpEF.

A comparative study on the bond features in CO, CS, and PbS.

Covalent and noncovalent interactions dominate most compounds in the condensed phase and gas phase. For a classical diatomic molecule CO, it is usually regarded as a triple-bond system with one dative bond. In this work, the photoelectron velocity-map imaging spectra of the CS and PbS anions were first measured. The two interactions have been intuitively understood by a comparative investigation of electrostatic potential (ESP) and bond features in CO, CS, and PbS. It is suggested that both electrostatic and dative covalent interactions compete in CO molecules, while dative covalent interaction prevails in CS molecules and electrostatic interaction dominates in PbS molecules. As a consequence, CO has a very small dipole moment (∼0.1 D) compared to the large dipole moment in CS (>1.8 D) and PbS (>4 D). It is indicated that the electron affinity value increases with the increasing dipole moment in the order of CO < CS < PbS. In addition, intriguing ESP with negative bond-ends and positive bond-cylindrical-surface in CO is also revealed by comparing with that in CS and PbS. In the latter, the two molecules present opposite ESP maps. Molecular orbital analyses indicate surprising participation of Pb 5d orbitals in the Pb-S chemical bonding although Pb belongs to main-group elements. Further bond analyses using electron localization function, natural resonance theory, and bond order methods suggest that covalence is dominant in CS and ionicity is a major component in PbS, but somewhere in between for CO molecules. By a comparative study in this work, the CS molecule is also revealed as a promising ligand molecule for the transition-metal coordination chemical synthesis.

Ultraviolet photodissociation dynamics of the n-propyl and i-propyl radicals.

Ultraviolet (UV) photodissociation dynamics of jet-cooled n-propyl (n-C3H7) radical via the 3s Rydberg state and i-propyl (i-C3H7) radical via the 3p Rydberg states are studied in the photolysis wavelength region of 230-260 nm using high-n Rydberg atom time-of-flight and resonance enhanced multiphoton ionization techniques. The H-atom photofragment yield spectra of the n-propyl and i-propyl radicals are broad and in good agreement with the UV absorption spectra. The H + propene product translational energy distributions, P(E(T))'s, of both n-propyl and i-propyl are bimodal, with a slow component peaking around 5-6 kcal/mol and a fast one peaking at ∼50 kcal/mol (n-propyl) and ∼45 kcal/mol (i-propyl). The fraction of the average translational energy in the total excess energy, 〈f(T)〉, is 0.3 for n-propyl and 0.2 for i-propyl, respectively. The H-atom product angular distributions of the slow components of n-propyl and i-propyl are isotropic, while that of the fast component of n-propyl is anisotropic (with an anisotropy parameter ∼0.8) and that of i-propyl is nearly isotropic. Site-selective loss of the ß hydrogen atom is confirmed using the partially deuterated CH3CH2CD2 and CH3CDCH3 radicals. The bimodal translational energy and angular distributions indicate two dissociation pathways to the H + propene products in the n-propyl and i-propyl radicals: (i) a unimolecular dissociation pathway from the hot ground-state propyl after internal conversion from the 3s and 3p Rydberg states and (ii) a direct, prompt dissociation pathway coupling the Rydberg excited states to a repulsive part of the ground-state surface, presumably via a conical intersection.

State-dependent photoionization cross-sections of 3d transition metal atoms.

Using the saturation method, we measured the absolute photoionization cross-sections of several excited states of titanium, vanadium, chromium, iron, and cobalt. These results are reported for the first time in this paper. The measured values range from 0.4 ± 0.1 Mb to 6.9 ± 2.0 Mb. The results show that the photoionization cross-section depends on the atomic state and not just on the electronic configuration.