Natural calcium targets were bombarded with $\gamma$ rays from a 31-MeV betatron at several bremsstrahlung end-point energies. Angular and energy distributions of photoprotons were measured. In addition, the $\gamma$-ray spectra emerging from the thick target were recorded at several angles. They were used to study the $\gamma$ rays accompanying the decay of excited residual nuclei formed in the reactions ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}(\gamma ,p)$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}(\gamma ,n)$. The analysis yielded the following results for the main reaction channels: the energy dependence of the cross sections, the energy dependence of photoproton angular distributions, and the bremsstrahlung-weighted angular distributions of deexcitation $\gamma$ rays. According to the experimental results the following amplitudes seem to dominate in the particle channels: $f_{\frac{5}{2}}$ waves for the ($\gamma ,p_0$) reaction, $p_{\frac{3}{2}}$ waves for ($\gamma ,p_1$), and $p$ waves for reaction channels in which the residual nuclei are left in states above 4.93 MeV. This is consistent with the giant dipole state configuration, predicted on the basis of the shell-model bound-state calculation by Gillet and Sanderson. The agreement with continuum theories is less satisfactory. It is also found that the shapes of cross sections are more uniform and that the angular distributions are less energy-dependent than expected from theory. The ($\gamma ,p_1$) cross section was separated into $S=0\mathrm{}$ and $S=1\mathrm{}$ channel spin contributions of which only the dominant $S=0\mathrm{}$ part shows a resonant structure. Negative-parity hole channels bear evidence for two-step reaction processes and impurities in the ground state of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$. Ratios of ($\gamma ,p$) and ($\gamma ,n$) cross sections imply an admixture of less than 3% of $T=0\mathrm{}$ strength in the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ giant dipole resonance.

[NUCLEAR REACTIONS ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}(\gamma ,p)$, ($\gamma ,p{\gamma }^{\prime }$), and ($\gamma ,n{\gamma }^{\prime }$), $E_{\gamma }=11-30\mathrm{}$ MeV; measured $\sigma (E,\vartheta )$ to states of residual nuclei; deduced reaction-channel configurations.]

The cross section for the reaction ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}(\gamma ,p){}_{}{}^{25}{}_{}{}^{}\mathrm{Na}$ has been measured from 15 to 60 MeV using bremsstrahlung activation methods to obtain the yield curve. The peak cross section of 15.7 mb occurs at 22.6 MeV. Prominent secondary maxima occur at 29.6, 49.0, and 57.9 MeV. The cross section integrated to 28 MeV is 80 ± 9 MeV mb. The cross section integrated to 60 MeV is 161 ± 18 MeV mb. A discussion of our results and comparison with photoneutron data for ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$ from other sources is given.

[NUCLEAR REACTIONS ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}(\gamma ,p)$, $E=15-60\mathrm{}$ MeV; measured bremsstrahlung yield; deduced $\sigma \mathrm{}\left(E\right)\mathrm{}$.]

Fission probability distributions have been measured by ($t,pf$), ($t,\alpha f$), ($t,t^{\prime }f$), ($p,p^{\prime }f$), (${}_{}{}^3{}_{}{}^{}\mathrm{He},df$), and (${}_{}{}^3{}_{}{}^{}\mathrm{He},\alpha f$) reactions with bombarding energies of 15, 16, 20, 22.5, 24, and 24 MeV, respectively. Using targets of ${}_{}{}^{230,232}{}_{}{}^{}\mathrm{Th}$, ${}_{}{}^{231}{}_{}{}^{}\mathrm{Pa}$, ${}_{}{}^{234,236,238}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{237}{}_{}{}^{}\mathrm{Np}$, ${}_{}{}^{240,242}{}_{}{}^{}\mathrm{Pu}$, ${}_{}{}^{243}{}_{}{}^{}\mathrm{Am}$, and ${}_{}{}^{248}{}_{}{}^{}\mathrm{Cm}$ the fission decay of ${}_{}{}^{230,232,234}{}_{}{}^{}\mathrm{Th}$, ${}_{}{}^{232,236,238,240}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{238,242,244}{}_{}{}^{}\mathrm{Pu}$, and ${}_{}{}^{244,248,250}{}_{}{}^{}\mathrm{Cm}$ was studied. Subbarrier vibrational resonances were observed for ${}_{}{}^{234}{}_{}{}^{}\mathrm{Th}$, ${}_{}{}^{236,238,240}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{242}{}_{}{}^{}\mathrm{Pu}$, and ${}_{}{}^{250}{}_{}{}^{}\mathrm{Cm}$. The results are analyzed with a statistical model which involves resonant penetration of the double-humped fission barrier. Estimates of the heights and curvature of the two peaks in the fission barrier are obtained for Th, U, Pu, and Cm isotopes and these values are compared with various theoretical calculations.

[NUCLEAR REACTIONS FISSION measured fission probabilities, $E^{*}\le 7.5$ MeV for ${}_{}{}^{230,232,234}{}_{}{}^{}\mathrm{Th}$, ${}_{}{}^{232,236,238,240}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{238,242,244}{}_{}{}^{}\mathrm{Pu}$, ${}_{}{}^{244,248,250}{}_{}{}^{}\mathrm{Cm}$ using ($t,pf$), ($t,\alpha f$), ($t,t^{\prime }f$), ($p,p^{\prime }f$), (${}_{}{}^3{}_{}{}^{}\mathrm{He},df$), (${}_{}{}^3{}_{}{}^{}\mathrm{He},\alpha f$) reactions; deduced heights and curvatures for the double-peaked fission barrier for each case.]

We postulate a mixing of the states of the ground rotational band with those of an excited one, whose intrinsic excitation energy changes with angular momentum. This is shown to restore agreement with experiment for the variable-moment-of-inertia model up to all observed values of angular momentum.

[NUCLEAR STRUCTURE rare-earth nuclei ${}_{}{}^{158,160}{}_{}{}^{}\mathrm{Dy}$; ${}_{}{}^{158,160,162}{}_{}{}^{}\mathrm{Er}$, ${}_{}{}^{166}{}_{}{}^{}\mathrm{Yb}$, calculated high-angular-momentum levels of the ground rotational band. The band-mixing semiphenomenological model.]

The Lindhard and Winther equations for the transient magnetic field effect have been numerically integrated with the inclusion of a decays-in-flight correction and using the best available stopping power formulas. The calculations are carried out for an iron host and curves are generated from which the transient-field angular shift may be predicted for any $Z>\mathrm{}12\mathrm{}$ to an accuracy of ∼ 20%. The transient-field calculations are employed in the analysis of angular shift data for the first $2^{+}$ states of ${}_{}{}^{104}{}_{}{}^{}\mathrm{Pd}$, ${}_{}{}^{106}{}_{}{}^{}\mathrm{Pd}$, ${}_{}{}^{108}{}_{}{}^{}\mathrm{Pd}$, and ${}_{}{}^{110}{}_{}{}^{}\mathrm{Pd}$ isotopes implanted into an ${\mathrm{Fe}}_{0.8}$-${\mathrm{Co}}_{0.2}$ alloy and for ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$ and ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$ implanted into iron. The $g$ factors of the six isotopes are obtained and the hyperfine field of Pd in the alloy is determined. Evidence is presented which suggests that the hyperfine fields measured in oxygen beam implantation perturbed-angular-correlation experiments for Ru, Pd, Cd, and Te in Fe are consistently reduced from the hyperfine fields measured by other methods. In light of these results and the decays-in-flight corrections to the transient-field theory, angular shift data of previous workers on even-even isotopes of Ge, Ru, Pd, Cd, and Te have been reanalyzed. With the exception of ${}_{}{}^{70}{}_{}{}^{}\mathrm{Ge}$, all the $g$ factors are in agreement with a collective model.

[NUCLEAR REACTIONS ce, transient-field IMPAC technique. Measured $\gamma \left(\theta \right)$, deduced hyperfine fields, $g\left(2^{+}\right)$ for ${}_{}{}^{104,106,108,110}{}_{}{}^{}\mathrm{Pd}$ in ${\mathrm{Fe}}_{0.8}$-${\mathrm{Co}}_{0.2}$, for ${}_{}{}^{54,56}{}_{}{}^{}\mathrm{Fe}$ in Fe. Reanalysis of previous $g\left(2^{+}\right)$ for ${}_{}{}^{70,72,74,76}{}_{}{}^{}\mathrm{Ge}$, ${}_{}{}^{98,100,102,104}{}_{}{}^{}\mathrm{Ru}$, ${}_{}{}^{104,106,108,110}{}_{}{}^{}\mathrm{Pd}$, ${}_{}{}^{110,112,114,116}{}_{}{}^{}\mathrm{Cd}$, ${}_{}{}^{120,122,124,126,128,130}{}_{}{}^{}\mathrm{Te}$.]

The energy spacings of rotational levels in $K^{\pi }={\frac{3}{2}}^{-}$ bands in odd-neutron rare-earth nuclei are seen to exhibit an alternating behavior with the level spin. This behavior is analyzed empirically, phenomenologically, and theoretically. It is shown that the alternating term in phenomenological rotational energy expression is even more significant than the usual $I^2{\mathrm{}(I+1\mathrm{})\mathrm{}}^2$ correction term in most of the nuclei. Theoretical calculations employing Nilsson-model single-particle orbitals and including the contributions of admixtures from various $N=5\mathrm{}$ oscillator shell ${\mathrm{½}}^{-}$ single-particle states to perturb the rotational levels based on ${\frac{3}{2}}^{-}\mathrm{}\left[521\right]\mathrm{}$ states show that this behavior may reasonably be described as resulting from the third-order perturbation effects of the Coriolis interaction term in the Hamiltonian.

[NUCLEAR STRUCTURE Odd-$N$ even-$Z$ rare-earth nuclei, calculated Coriolis perturbation effects to $K=\frac{3}{2}$ rotational band levels.]

The cross section for $\gamma$-ray emission associated with inelastic scattering of neutrons in the ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}(n,n^{\prime }\gamma ){}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ reaction has been measured at several angles for neutron energies between 3.1 and 5.25 MeV. The experimental data have been compared with calculations based on the Satchler formalism, with allowance for width-fluctuation corrections. Agreement for the 2.61-MeV $\gamma$ ray is excellent throughout. The experimentally observed cross sections for the other $\gamma$ rays were generally 30 to 50% below the theoretical values, except for the 0.583-MeV $\gamma$ ray, for which the observed values were well above the theoretical values. Resolution of several $\gamma$-ray peaks with a Ge(Li) detector has led to a modified level scheme for ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$.

[NUCLEAR REACTIONS ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}(n,n^{\prime }\gamma ){}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$, $E=3.1-5.25\mathrm{}$ MeV, measured $\sigma (E,\theta )$ for deexcitation $\gamma$ rays. Compound nuclear theory analysis, including width fluctuations.]

$\gamma$ rays following slow-neutron capture in natural ruthenium have been studied. Spin and isotopic assignments for resonances have been made based on high- and low-energy $\gamma$-ray transitions. In the case of the product nuclei ${}_{}{}^{100}{}_{}{}^{}\mathrm{Ru}$- ${}_{}{}^{102}{}_{}{}^{}\mathrm{Ru}$, the present ($n,\gamma$) studies extend our knowledge of the level schemes to energies higher than previously available from $\beta$-decay studies of Rh and Tc isotopes. A notable feature of the data is a relatively high concentration of radiation strength between 6.5 and 7.0 MeV for both ${}_{}{}^{100}{}_{}{}^{}\mathrm{Ru}$ and ${}_{}{}^{102}{}_{}{}^{}\mathrm{Ru}$. $M1\mathrm{}$ enhancement could be ascribed to a doorway state in neutron capture leading to spin-flip transitions of the $g_{\frac{7}{2}}\to g_{\frac{9}{2}}$ type.

[NUCLEAR REACTIONS ${}_{}{}^{99,101}{}_{}{}^{}\mathrm{Ru}(n,\gamma )$ $E_n=0.0253\mathrm{} \mathrm{to} 230$ eV, deduced resonance spins, isotopic identifications, partial widths ${\Gamma }_{\gamma \lambda f}$; ${}_{}{}^{100,102}{}_{}{}^{}\mathrm{Ru}$ levels, spin, and parities.]

A new determination of the ${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$ specific activity has been made using a method developed for measuring the longer-lived uranium isotopes. Samples prepared by molecular plating were counted in an intermediate-geometry $\alpha$ proportional counter with a flat pulse-height plateau. For each sample, the small amount of residual non-plated uranium was evaluated by counting in a $2\pi$ counter. Energy analysis with a silicon-junction detector allowed accurate measurement of the small amount of activity not ascribable to ${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$ and ${}_{}{}^{234}{}_{}{}^{}\mathrm{U}$. The ${}_{}{}^{234}{}_{}{}^{}\mathrm{U}$ activity was corrected for by calculation from the mass-spectroscopically-measured isotopic concentration. The specific activity was measured as 21 405 ± 20-dis/min μg ${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$, corresponding to a half-life of (1.5911 ± 0.0015) × ${10}^5$ yr. The quoted error is statistical (standard error of the mean), based upon observed scatter of the data.

[RADIOACTIVITY ${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$; measured $T_{\frac{1}{2}}$.]

The levels of ${}_{}{}^{95,97}{}_{}{}^{}\mathrm{Mo}$ below 1.2 MeV in excitation have been studied with the ${}_{}{}^{94,96}{}_{}{}^{}\mathrm{Mo}$(${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$,${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$) reactions. Relative cross sections to the very closely spaced excited states were determined by particle-$\gamma$ coincidence measurements. Generally excellent agreement between the measured cross sections and those calculated by a direct transfer code, which includes recoil correctly to first order, was found. The selectivity of this heavy-ion reaction was used to determine spin assignments which were ambiguous in light-ion experiments. The importance of two-step processes on the magnitude of the cross section was investigated. One state showed a strong enough deviation from distorted-wave Born-approximation calculations to suggest the influence of such two-step processes.

[NUCLEAR REACTIONS ${}_{}{}^{94,96}{}_{}{}^{}\mathrm{Mo}$(${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$), (${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$), $E=48.5-54.5\mathrm{}$ MeV; measured $\sigma (E,\theta )$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}\gamma$ coin; deduced optical-model parameters. DWBA analysis.]

The ($\alpha ,n$) cross section on ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ and ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ has been measured between 16 and 24 MeV by observing the $\alpha$ activity of the residual nuclei ${}_{}{}^{211}{}_{}{}^{}\mathrm{Po}$ and ${}_{}{}^{212}{}_{}{}^{}\mathrm{At}$. The relative yields to both the ground and metastable states of each residual nucleus were obtained and new half-life determinations have been made for these states. The absolute yield was measured at 20 and 22 MeV to normalize the relative data. Below the ($\alpha ,2n$) threshold, $\sigma (\alpha ,n)$ constitutes most of the total reaction cross section, and the ($\alpha ,n$) data, together with accurate elastic scattering measurements at 19, 20, and 22 MeV are reproduced well by a six-parameter optical model. The fits are sensitive to the reaction cross-section data, and serve to define the magnitude and shape of the real potential at a radial distance of about 11 fm. The real potential in this region dominates the interaction at the present energies. The imaginary potential is relatively small; it is not well determined and serves only to absorb those waves which penetrate the real potential. The real potential obtained is interpreted in terms of an $\alpha$-folding model using a free $\alpha$-nucleon two-body force. The potential near the peak of the Coulomb barrier is determined primarily by the target matter density near 9 fm, where it is approximately 1% of its value at the center of the nucleus. Implications concerning the relative distributions of target neutron and protons are discussed.

[NUCLEAR REACTIONS ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$, ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}(\alpha ,\alpha ) (\alpha ,n)$; measured $\sigma \left(\theta \right)$ elastic, $E_{\alpha }=19,20,22\mathrm{}$ MeV; ${\sigma }_{\alpha n}\mathrm{}\left(E\right)\mathrm{}$, $E_{\alpha }=16-24\mathrm{}$ MeV; $T_{\frac{1}{2}}$: ${}_{}{}^{211}{}_{}{}^{}\mathrm{Po}$, ${}_{}{}^{211}{}_{}{}^{}\mathrm{Po}_{}^m{}_{}{}^{}$, ${}_{}{}^{212}{}_{}{}^{}\mathrm{At}$, ${}_{}{}^{212}{}_{}{}^{}\mathrm{At}_{}^m{}_{}{}^{}$. Deduced optical potentials, surface matter density form factors.]

On-line atomic-beam-magnetic-resonance experiments at the Princeton cyclotron were used to measure the magnetic hyperfine structure transitions involving the isomeric state of ${}_{}{}^{102}{}_{}{}^{}\mathrm{Ag} (T_{\frac{1}{2}}=8\mathrm{} min, I=2)$ and the ground state of ${}_{}{}^{106}{}_{}{}^{}\mathrm{Ag} (T_{\frac{1}{2}}=24\mathrm{} \mathrm{s}, I=6)$. The radioactive nuclei were formed by a ($p,n$) reaction on palladium inside the oven of the atomic beam apparatus. The values of magnetic dipole interaction constant are $A\left(102\right)=15\mathrm{}060\pm 900$ MHz and $A\left(106\right)=20\mathrm{}345\pm 600$ MHz. From these measurements we infer the values of the nuclear magnetic dipole moments to be $\mu \mathrm{}\left(102\right)=+(4.12\mathrm{}\pm 0.25){\mu }_N$ and $\mu \mathrm{}\left(106\right)=+(2.83\mathrm{}\pm 0.2){\mu }_N$.

[NUCLEAR MOMENTS ${}_{}{}^{102}{}_{}{}^{}\mathrm{Ag}_{}^m{}_{}{}^{}$, ${}_{}{}^{106}{}_{}{}^{}\mathrm{Ag}_{}^g{}_{}{}^{}$; measured $a$, $g_I$; deduced ${\mu }_I$. Atomic beam magnetic resonance.]

An analysis of elastic electron scattering from the nuclear charge and magnetization distributions is carried out with phase-shift analysis and distorted-wave Born approximation, respectively. We find that magnetic electron scattering should be measurable from medium and heavy odd-$A$ nuclei at normal scattering angles in addition to 180°. In particular, the scattering from the maximally allowed magnetic multipole distribution should be easily observed.

[NUCLEAR REACTIONS ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$, ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ elastic $e^{-}$ scattering from magnetic moments odd-$A$ nuclei calculated (phase shift and DWBA).]

Strongly selected states at high excitation energies in ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ are seen in both of the above reactions. In the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}({}_{}{}^{16}{}_{}{}^{}\mathrm{O},\alpha ){}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ case, the energy dependence of the strongest transitions seen suggests that it is related to entrance-channel structure. Large differences in selectivity of the two reactions further indicate a sensitivity to the intrinsic structures of the initial states.

A recent phase-shift analysis of $p-p$ scattering from 0-500 MeV has been used to calculate the average Coulomb rotation of the forward nuclear $p-p$ amplitude in this energy range. We find that the rotated amplitude is well represented over this energy range by the unrotated amplitude (the imaginary part of which is related to the total cross section) times a rotation of about 1-2°. This rotation factor should be included in extrapolations of precise $p-p$ differential cross sections through the Coulomb peak.

[NUCLEAR REACTION $(p-p)(p-p)E=0-500\mathrm{}$ MeV. Calculation of Coulomb rotation effects on forward nuclear amplitude. From analytic partial-wave representation of elastic data.]

We present an analytical expression for the shape factor for the $\beta$ decay of ${}_{}{}^{12}{}_{}{}^{}\mathrm{B}$ with the Coulomb corrections to order $\alpha \mathrm{ZR}{W}_0$, including the correction through the induced weak magnetism term and examine effects of this induced Coulomb correction.

[RADIOACTIVITY ${}_{}{}^{12}{}_{}{}^{}\mathrm{B}$; calculated $\sigma \left(E_e\right)$, Coulomb corrections.]

More detailed information is presented concerning the $L$ and $K$ x-ray spectra due to internal conversion of the electromagnetic transitions following the $\alpha$ decay of ${}_{}{}^{231}{}_{}{}^{}\mathrm{Pa}$. Some of the difficulties discussed in Ref. 1 are clarified by the new results.

[RADIOACTIVITY ${}_{}{}^{231}{}_{}{}^{}\mathrm{Pa}$; measured $L$ and $K$ Ac x-ray components, $\gamma \gamma$ and $\gamma X_L$ coin ${}_{}{}^{227}{}_{}{}^{}\mathrm{Ac}$ deduced levels, ICC.]

Experiments to measure the photoneutron yield from a liquid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ target as a function of beam intensity have been carried out. They show that the most recent measurements of the photoneutron cross section with liquid helium targets can be made consistent with each other, and that the results are then not inconsistent with measurements of the ${}_{}{}^4{}_{}{}^{}\mathrm{He}(\gamma ,n){}_{}{}^3{}_{}{}^{}\mathrm{He}$ cross section using gaseous targets.

[NUCLEAR REACTIONS ${}_{}{}^4{}_{}{}^{}\mathrm{He}(\gamma ,n)$, $E=35\mathrm{}$ MeV; measured $\sigma$ (beam current).]

Previous discrepancies in the reported values of the nuclear magnetic dipole moment of the 171-keV level of ${}_{}{}^{191}{}_{}{}^{}\mathrm{Ir}$ measured by nuclear orientation and nuclear magnetic resonance techniques are resolved by an interpretation in terms of nonalignment of the static magnetic hyperfine field of Ir in Fe with the applied field. The angle between the applied and hyperfine field directions is deduced to be 15°. Other possible sources of the discrepancies in the reported moments are shown to be negligible. The best value of the moment is believed to be $\mu =(6.03\mathrm{}\pm 0.04){\mu }_N$ measured by Eska et al. using NMR techniques.

[RADIOACTIVITY ${}_{}{}^{191}{}_{}{}^{}\mathrm{Ir}_{}^m{}_{}{}^{}$; measured $\gamma (\theta ,T)$ in Fe; deduced nonalignment of hyperfine field.]

The reactions ($\alpha , {}_{}{}^9{}_{}{}^{}\mathrm{Be}$), ($\alpha , {}_{}{}^7{}_{}{}^{}\mathrm{Be}$), and (${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^8{}_{}{}^{}\mathrm{B}$) on ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$ at $E\left(\alpha \right)=78\mathrm{}$ MeV and $E\left({}_{}{}^6{}_{}{}^{}\mathrm{Li}\right)=80\mathrm{}$ MeV were used to determine the mass excesses of ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ar}$ (-31.98 ± 0.07 MeV), ${}_{}{}^{45}{}_{}{}^{}\mathrm{Ar}$(-29.727 ± 0.06 MeV), and ${}_{}{}^{46}{}_{}{}^{}\mathrm{Ar}$ (-29.732 ± 0.07 MeV) by counter telescope techniques. Excited states in ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ar}$ at 1.74 ± 0.05, 2.55 ± 0.05, 3.56 ± 0.07, and 4.74 ± 0.10 MeV and in ${}_{}{}^{45}{}_{}{}^{}\mathrm{Ar}$ at 1.66 ± 0.05, 2.42 ± 0.05, and 3.25 ± 0.07 MeV were also observed. Comparisons are made with mass predictions calculated from simple mass relations based on the shell model and with those obtained from the Garvey and Kelson approach.

[NUCLEAR REACTIONS ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}(\alpha ,{}_{}{}^9{}_{}{}^{}\mathrm{Be})$, ($\alpha , {}_{}{}^7{}_{}{}^{}\mathrm{Be}$), $E=78\mathrm{}$ MeV; ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$(${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^8{}_{}{}^{}\mathrm{B}$), $E=80\mathrm{}$ MeV; ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ar}$, ${}_{}{}^{45}{}_{}{}^{}\mathrm{Ar}$, ${}_{}{}^{46}{}_{}{}^{}\mathrm{Ar}$ measured mass excesses, excitation energies; compared mass predictions.]