Soluble Semiconductors AAsSe2 (A = Li, Na) with a Direct-Band-Gap and Strong Second Harmonic Generation: A Combined Experimental and Theoretical Study
Tarun K. Bera; Joon I. Jang; Jung-Hwan Song; Christos D. Malliakas; Arthur J. Freeman; John B. Ketterson; Mercouri G. Kanatzidis; Journal of the American Chemical Society 132 (2010) 3484–3495; doi:10.1021/ja9094846

data_4102047
_publ_section_title
;
 Soluble Semiconductors AAsSe2 (A = Li, Na) with a Direct-Band-Gap and
 Strong Second Harmonic Generation: A Combined Experimental and
 Theoretical Study
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              3484
_journal_page_last               3495
_journal_paper_doi               10.1021/ja9094846
_journal_volume                  132
_journal_year                    2010
_chemical_formula_sum            'As Na Se2'
_chemical_formula_weight         255.83
_chemical_name_systematic
; 
 ? 
;
_space_group_IT_number           7
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P -2yc'
_symmetry_space_group_name_H-M   'P 1 c 1'
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.446(13)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   11.682(2)
_cell_length_b                   5.9021(7)
_cell_length_c                   11.8231(19)
_cell_measurement_reflns_used    5842
_cell_measurement_temperature    100
_cell_measurement_theta_max      29.18
_cell_measurement_theta_min      3.45
_cell_volume                     815.2(2)
_computing_cell_refinement       X-area
_computing_data_collection       X-area
_computing_data_reduction        X-area
_computing_molecular_graphics    Diamond
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      100
_diffrn_measured_fraction_theta_full 0.951
_diffrn_measured_fraction_theta_max 0.951
_diffrn_measurement_device_type  IPDS2
_diffrn_measurement_method       'profile data from \w scan'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0633
_diffrn_reflns_av_sigmaI/netI    0.0578
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -16
_diffrn_reflns_number            5842
_diffrn_reflns_theta_full        29.18
_diffrn_reflns_theta_max         29.18
_diffrn_reflns_theta_min         3.45
_exptl_absorpt_coefficient_mu    26.062
_exptl_absorpt_correction_T_max  0.7028
_exptl_absorpt_correction_T_min  0.0435
_exptl_absorpt_correction_type   numerical
_exptl_absorpt_process_details   XRED32
_exptl_crystal_colour            red
_exptl_crystal_density_diffrn    4.169
_exptl_crystal_density_meas      4.169
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             896
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.09
_exptl_crystal_size_min          0.06
_refine_diff_density_max         2.099
_refine_diff_density_min         -1.874
_refine_diff_density_rms         0.400
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.04(6)
_refine_ls_extinction_coef       0.0010(2)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.130
_refine_ls_matrix_type           full
_refine_ls_number_parameters     148
_refine_ls_number_reflns         3339
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.130
_refine_ls_R_factor_all          0.0653
_refine_ls_R_factor_gt           0.0501
_refine_ls_shift/su_max          2.980
_refine_ls_shift/su_mean         0.020
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0611P)^2^+22.8782P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1169
_refine_ls_wR_factor_ref         0.1363
_reflns_number_gt                2898
_reflns_number_total             3339
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja9094846_si_002_3.cif
_cod_data_source_block           gamma-NaAsSe2
_cod_database_code               4102047