MsSpec-DFM/New_libraries/DFM_library/DAMPING_LIBRARY/decay_rate.f90

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2022-02-02 16:19:10 +01:00
!
!=======================================================================
!
MODULE DECAY_RATE
!
USE ACCURACY_REAL
!
!
CONTAINS
!
!=======================================================================
!
SUBROUTINE DECAY_RATE_COEF(X,DR)
!
! This subroutine computes the decay rate
!
!
! Input parameters:
!
! * X : dimensionless factor --> X = q / (2 * k_F)
!
!
! Output parameters:
!
! * DR : decay rate
!
!
!
! Author : D. Sébilleau
!
! Last modified : 12 Nov 2020
!
!
USE MATERIAL_PROP, ONLY : DMN,RS
USE EXT_FIELDS, ONLY : T
USE LF_VALUES, ONLY : GQ_TYPE,IQ_TYPE
USE SF_VALUES, ONLY : SQ_TYPE
!
USE DAMPING_VALUES, ONLY : DR_TYPE
!
IMPLICIT NONE
!
REAL (WP), INTENT(IN) :: X
REAL (WP), INTENT(OUT) :: DR
!
IF(DMN == '3D') THEN !
CALL DECAY_RATE_3D(X,T,RS,DR_TYPE,SQ_TYPE,GQ_TYPE, & !
IQ_TYPE,DR) !
ELSE IF(DMN == '2D') THEN !
CONTINUE ! not implemented yet
ELSE IF(DMN == '1D') THEN !
CONTINUE ! not implemented yet
END IF !
!
END SUBROUTINE DECAY_RATE_COEF
!
!=======================================================================
!
SUBROUTINE DECAY_RATE_3D(X,T,RS,DR_TYPE,SQ_TYPE,GQ_TYPE, &
IQ_TYPE,DR)
!
! This subroutine computes the plasmon decay rate
!
!
! Input parameters:
!
! * X : dimensionless factor --> X = q / (2 * k_F)
! * T : temperature (in SI)
! * RS : Wigner-Seitz radius (in units of a_0)
! * DR_TYPE : type of decay rate
! DR_TYPE = 'UTIC' --> Utsumi-Ichimaru approximation
! DR_TYPE = 'VLAS' --> Vlasov approximation
! * SQ_TYPE : structure factor approximation (3D)
! * GQ_TYPE : local-field correction type (3D)
! * IQ_TYPE : type of approximation for I(q)
!
! Output parameters:
!
! * DR : decay rate
!
!
!
! Author : D. Sébilleau
!
! Last modified : 11 Jun 2020
!
!
!
IMPLICIT NONE
!
CHARACTER (LEN = 4) :: DR_TYPE,GQ_TYPE
CHARACTER (LEN = 3) :: SQ_TYPE,IQ_TYPE
!
REAL (WP) :: X,T,RS
REAL (WP) :: DR
!
IF(DR_TYPE == 'UTIC') THEN !
DR=UTIC_DR_3D(X,RS,T,SQ_TYPE,GQ_TYPE,IQ_TYPE) !
ELSE IF(DR_TYPE == 'VLAS') THEN !
DR=VLAS_DR_3D(X,T,RS) !
END IF !
!
END SUBROUTINE DECAY_RATE_3D
!
!=======================================================================
!
FUNCTION UTIC_DR_3D(X,RS,T,SQ_TYPE,GQ_TYPE,IQ_TYPE)
!
! This function computes Utsumi-Ichimaru approximation for
! the decay rate in the 3D case
!
! Reference: (1) K. Utsumi and S. Ichimaru,
! Phys. Rev. B 22, 1522-1533 (1980)
!
!
! Input parameters:
!
! * X : dimensionless factor --> X = q / (2 * k_F)
! * RS : Wigner-Seitz radius (in units of a_0)
! * T : temperature (in SI)
! * SQ_TYPE : structure factor approximation (3D)
! * GQ_TYPE : local-field correction type (3D)
! * IQ_TYPE : type of approximation for I(q)
!
! Output parameters:
!
! * UTIC_DR : decay rate
!
! Author : D. Sébilleau
!
! Last modified : 3 Dec 2020
!
!
USE REAL_NUMBERS, ONLY : HALF
USE CONSTANTS_P1, ONLY : H_BAR
USE UTIC_PARAMETERS, ONLY : UTIC_PARAM
USE RELAXATION_TIME_STATIC, ONLY : UTIC_RT_3D
USE PLASMON_ENE_SI
!
IMPLICIT NONE
!
CHARACTER (LEN = 4) :: GQ_TYPE
CHARACTER (LEN = 3) :: SQ_TYPE,IQ_TYPE
!
REAL (WP), INTENT(IN) :: X,RS,T
REAL (WP) :: UTIC_DR_3D
!
REAL (WP) :: OMP
REAL (WP) :: TAU_Q,OMQ,OM0
!
REAL (WP) :: EXP
!
OMP = ENE_P_SI / H_BAR ! omega_p in SI
!
! Computing the Utsumi-Ichimaru parameters OMEGA(q) and OMEGA(0)
!
CALL UTIC_PARAM(X,RS,T,OMQ,OM0) !
!
! Computing the relaxation time TAU_Q
!
TAU_Q = UTIC_RT_3D(X,RS,T,SQ_TYPE,GQ_TYPE) !
!
UTIC_DR_3D = - HALF * EXP(- HALF * (OMP / OM0)**2) / TAU_Q ! ref. 1 eq. (5.13)
!
END FUNCTION UTIC_DR_3D
!
!=======================================================================
!
FUNCTION VLAS_DR_3D(X,RS,T)
!
! This function computes Vlasov approximation for
! the decay rate in the 3D case
!
! Reference: (1) S. Ichimaru, "Statistical Plasma Physics - Vol1",
! CRC Press (2004)
!
!
! Input parameters:
!
! * X : dimensionless factor --> X = q / (2 * k_F)
! * RS : Wigner-Seitz radius (in units of a_0)
! * T : temperature (in SI)
!
! Output parameters:
!
! * VLAS_DR : relaxation time in seconds
!
! Author : D. Sébilleau
!
! Last modified : 11 Jun 2020
!
!
USE REAL_NUMBERS, ONLY : TWO,THREE,HALF
USE CONSTANTS_P1, ONLY : H_BAR,M_E,K_B
USE FERMI_SI, ONLY : KF_SI
USE PI_ETC, ONLY : PI
USE SCREENING_VEC, ONLY : DEBYE_VECTOR
USE PLASMON_ENE_SI
!
IMPLICIT NONE
!
REAL (WP) :: X,RS,T
REAL (WP) :: VLAS_DR_3D
REAL (WP) :: Q_SI,KD_SI,OQ2,AA
!
REAL (WP) :: DSQRT,DEXP
!
Q_SI=TWO*X*KF_SI ! q
!
! Computing the Debye screening vector
!
CALL DEBYE_VECTOR('3D',T,RS,KD_SI) !
!
! Computing the square of the Vlasov plasmon dispersion
!
OQ2=ENE_P_SI*ENE_P_SI + THREE*K_B*T*Q_SI*Q_SI/M_E ! ref. 1 eq. (4.30)
!
AA=HALF*M_E*OQ2/(Q_SI*Q_SI*K_B*T) !
!
VLAS_DR_3D=DSQRT(0.125E0_WP*PI)*ENE_P_SI*(KD_SI/Q_SI)**3 * & ! ref. 1 eq. (4.31)
DEXP(-AA) / H_BAR !
!
END FUNCTION VLAS_DR_3D
!
END MODULE DECAY_RATE